Newsflash: Buying a house from my parents.

I am a first time buyer and I need advice. I’m buying a house from my parents. He wants $240k. I only make $2700 a months and when I spoke with a lender they said the estimated monthly cost including taxes and insurance would be around $1800. That would only leave me with $900. Is this smart? My mom and step dad are getting divorced and she will continue to live in the house with me (she can’t afford to live on her own). I already know the water heater and hvac system needs to be replaced. What are some steps that I can take to protect myself in this transaction? I don’t have a lawyer, will be using my parents lawyers.