Who's name should be on the purchase agreement?

[Seth Savoy]

A friend of mine has a grandmother who will be placed in a nursing home in the very near future. Her house is in need of some major repairs, and has a tax lien against it. To make the situation even more complicated, her son has power of attorney and will be handling the sale of the house. Here are my questions: 1-Do I need to take care of the tax liens before I can close on the house? 2-Should the purchase agreement have the mother's name or the son's? He will be the one signing for her. 3- Where can I find a purchase agreement and an assignment contract for the state of Texas?