Stella, I answered your 3 questions.
But apart from that, reading your post again - why doesn't your friend just let this house be your man's problem from now on? He lives there, he pays the mortgage in full, he maintains it, he pays the property tax, house Insurance and life assurance. She doesn't have to have anything to do with it. This will work as long as he pays the mortgage.
What could happen is that if he lets it go into arrears it will affect her credit rating. If she doesn't trust him to pay the mortgage or to keep up the other payments or maintain it, then she might be better off preventing him from moving back in (in so far as she can)