Can someone have a villager move to their island if they have a villager in boxes?

My friend has all of their plots full, and one of their villagers is in boxes right now. They are offering for Tex, who’s on my island, and I have to get him in boxes today since Freya is in my campsite and I really want her to move in.

If I get Tex in boxes, is it possible for my friend to come and adopt Tex if they have full plots, but they have a villager in boxes?