My name isXXXXX a licensed attorney. Glad to try and help out.
Sure sorry for the circumstances, truly. My heart goes out to you. I say that in all sincerity, as I'm such a pet lover and can only image how much you're going through at this time, not to mention the loss of your home.
Accordingly, I'm pleased to share some good news with you, as follows.
As long as your friend is agreeable to the arrangements, you're in good shape. Here's what I mean by that statement. The law provides that each marital party enjoys shared rights to their domicile. This includes what the law calls the quiet use and enjoyment of the home, and that means having guests over, having animals, smoking (if applicable) and so forth. Now, he can certainly express his views, but there is nothing the man can do to "force" his wife to not allow the pets to be boarded. The only thing that could make his wishes "stick" would be for him to obtain a Court Order, which just isn't going to happen.
If you have a follow-up question or need clarification, please just say the word by using "reply" to reach me.
I truly hope all works out for you.