has she had a lot of contact with him yet? is she familiar with him? I guess those would be my first big questions.

If he has been around her and they interact with each other during the day....I would think it's okay. Just make sure you prepare her and let her know he will be sleeping at the house and that he will not hurt her. He is a safe man that wants to care about her and keep her safe.

Make sure to ask her before what she thinks about it and validate whatever she says...you don't necessarily need to do what she says, just let her know you understand what she is thinking/feeling and give her a chance to express it, if she is visibly scared or upset - maybe take that as a signal that this is too much for her right now.

I personally think she needs to see that not all men will hurt her...