GIFTING A HOUSE AFTER DEATH

I have a question my friend wants to gift me his house after he dies by signing his house over to me, I am in California his house is paid off but needs tons of work, how is this done and will I get in trouble for anything, he has no family relatives or anyone I am his sole friend that takes care of him. He is an elderly gentleman in his late 70's and he wants to leave his house to me. How can this be done legally and safely? Thanks.