to-infinitive+infinitive+pronoun (e.g., to Help Keep You)?

First, it is worthwhile to understand that

(a) “to help keep you secure” is a closely synonymous with “to assist your security”

(b) “to help you keep secure” is a closely synonymous with “to assist you in keeping yourself secure.”

I found the sentence: "to help keep you safe and secure "

That is not a sentence… You need to add to it:

“We have fitted stronger locks to the door to help keep you safe and secure

In full, this is

1. “We have fitted stronger locks to the door in order to help keep you safe and secure.

In this, (i) keep is a bare infinitive and (ii) “you” is the object of “keep” and (iii) “safe and secure” is a compound adjective and the complement of “keep.”

The meaning thus emphasises that our fitting the locks is keeping you safe and secure.

Your alternative thus becomes

1. “We have fitted stronger locks to the door in order to help you keep safe and secure"

In this, keep is a bare infinitive and “you” is the object of “help” and “safe and secure” is a compound adjective and the complement of “keep.”

The meaning thus emphasises that our fitting the locks is helping you to be safe and secure.

The question is: What is the subject of keep?

(1) to help [ ___ keep you safe and secure ]

(2) to help you [ ___ keep safe and secure ]

In the first it is not clear what the subject of keep is without more context or the addition of some further element. In two, the understood subject is you. Compare:

(3) to help you [ ___ keep yourself safe and secure ]

With the reflexive pronoun it is clear that only the interpretation with you as subject of keep is possible.

When help has an object and a bare infinitival complement, it's understood that the subject of that bare infinitival is same as the object of help.

(1) is correct in situations where someone else is keeping you safe and secure, (2) where you are keeping yourself safe and secure. In (1) someone else is helped, in (2) you are helped.