Property sale proposal

[Randall E Collins]

This post is directed toward professionals who know real estate in and out. I own land and a fairly new mobile home in Henderson Co. Texas. I have stage four COPD and I'm not expected to live much longer. My daughter is the sole beneficiary of all my belongings upon my death. However, I have received an offer on my property from a very good and trustworthy friend that I have agreed to accept. I have spoken with my daughter and she has agreed as well. He has proposed to pay me a certain amount towards the sale of my property until my death. If I die before receiving the full purchase amount my friend will pay my daughter the remainder. Would someone please tell me what sort of contractual agreement should I draft and or title?"