I'm very exhausted giving ear drops to my overly skittish cat. I can't take him treating me like a threat. What should I do?

The truth of the matter is, while there are things you can do to attempt to lessen the problem, this will always be a problem to some extent because of course you can never convince a cat to like taking medicine. Most solutions involve lessening the problem in the long term, but since this situation is temporary, you do also have a few immediate term options available, such as asking a friend to help treat the cat just for now, or contacting the organization you're fostering with and asking for help, advice, or even for someone else to foster the cat.

That said, if you feel like this really is beyond what you are able to handle given your current situation, then absolutely it is wisest to not go through with adopting the cat. Rather than taking this experience as a failure, take it as a valuable lesson about what you are able or not able to do. It's perfectly okay if you realize this is not a responsibility you want long term, especially when you consider that I don't expect giving medicine to ever be completely smooth, and that if you permanently home the cat, you almost certainly will have to give it medicine again at some point in its life. Furthermore, though I really doubt that the cat will hate you forever just because it has to endure some weeks of ear drops, at the same time, you also have to be prepared that your own pet might become scared of you like this because you have to do something it doesn't like for its own good, and that you may even have to put in a lot of extra work to gain back its trust.

Anyways, as for the long term approach, you can try to accustom the cat as much as possible to these things by gradually working through each step of the process, one step at a time, over the course of days or weeks, giving treats as rewards to encourage the cat to accept it. Hopefully the cat will form positive associations, and lessen its stress when you actually have to do things it doesn't like.

The other key is to keep up these exercises outside the thing it doesn't like, so that the cat doesn't notice a pattern and get a bad association. The reason why the feeding plus the ear drops isn't working is because it's a predictable enough pattern that the cat is starting to form a negative association between ear drops and being fed, and so it automatically thinks it has to avoid the ear drops every time it gets fed now. You could try decreasing its portions and feeding more frequently, then giving the drops at irregular meal times to decrease the predictability, but I expect it's going to be difficult to break the bad association now.

For a more concrete example, with the carrier, start feeding the cat near the carrier. Over the course of days, move the dish closer and closer, until the dish is all the way inside, and the cat is happily eating. The next step is getting it to accept you closing the door. Keep feeding the cat in the carrier from them on, and then when you need to go to the vet, just feed the cat, and hopefully it'll go right in.

Getting it used to accepting medicine is harder, and honestly no matter what you do there'll surely be some level of stress, because like I said, no cat likes receiving medicine. But I would try using a similar sort of strategy with treats to work up the cat into allowing you to restrain it long enough to give some medication, particularly its head.

Repitition, Routine and Patience.

Three massive things in most animals lives.

You mention he keeps trying to hide and was becoming quite aggressive... I have to ask does he have enough safe spaces he can climb up onto? Cats need a lot of stimulation and can really benefit from having shelves and climing towers. This could boost his mood and make him more amenable. Don't forget to play with him daily. If he's ready to fight and that's out of character then he could just have excess energy.

I must admit him running away when you walked in and he was using the litter tray doesn't suggest that he's scared of you particularly it's more of he's unsure of what is his and what isn't along with he wasn't expecting you to be there at that moment in time.

Prior to the vet visit you unknowingly got yourself in a routine with this cat and their eardrops. Thus, although they were not happy to recieve them but they still begrudgingly put up with them but then one day the eardrops stopped and so he adapted to this new routine of not needing them applied.

Unfortunately as he put up quite a fight the last time you attempted to put ear drops in he's probably realised that this is a good way to get out of having the medication and will try to put up a fight from now on.

What would I do? If he's being very extreme and it's all getting a bit too much for you:

I would use an empty bottle of eardrops (or similarly shaped item,) first. Just get him used to the idea that the eardrop bottle isn't always a horrible experience. Sometimes the bottle will just be there to pet him or pop some tuna in it. This way he won't be trying to run anywhere instantly at the sight of the bottle.

Then you can progress to using the bottle in one hand and distracting with food or a toy with the other. Finally after some time you'll be able to do the eardrops and then give him his favourite treat/toy as a reward. It will never be pretty but this method should make it slightly easier.

important side note: I wouldn't interrupt his normal feeding time with this practice. You don't want to get him axious around food time you want to create a new event in his day.

I will say that we had a norweigian forest cat and in the last few months of his life had to give him painkillers in a paste. It was the hardest thing I've had to do to date. It was always a two man job, one to hold him down while the other fed him the paste and we had bought leather gloves just to deal with him biting and scratching us. He would run away once we were finished but it really doesn't matter. With an animal it's important to note that their wellbeing comes before how you're feeling personally. It broke my heart to see him that way but there was no other alternative.

I also know cat owners who dread defleeing and worming their cats as this too is also a fight. Unfortunately these things can't be avoided and we must battle through regardless of what the cat thinks of us after.

So, I commend you for coming this far, anxiety and extreme empathy aren't easy to live with when you have a pet but I promise you can pull through this. Remember, the cat doesn't necessarily think you're a threat. He's just not used to you. 2 months is still a short amount of time for an animal to acclimate to it's new surroundings and get into a solid routine.

If you're still struggling you can look up

"My Cat From Hell"

these series are bound to provide you with lots of ideas to help you and your cat.