Need help budgeting and investing Father’s inheritance

My Father (Age 56) recently sold the family land that he had inherited about a year ago. He has come into about $750k. Once everything finalizes he plans to have that money sit in his bank account. I don’t believe he has ever invested in stocks, mutual funds, ETFs before.

Some more background about him: He is a self-employed truck driver (living in North Dakota) that makes decent money, but I don’t really know how much he currently saves, if any. He has always had the philosophy that he can just work to make more money if he needs it. He’s socially connected, so he always seems to find trucking jobs when needed. And so far, he has always found a way to make money to live comfortably for his needs. Since he is getting older, I doubt this will always be the case.

He currently has 2 children who still live at home (each 14 years old) and about 5k worth of monthly expenses. He owns his house and his semi outright. He also plans to spend 50-100k on developing 100 acres of rural ND lakefront property he hung onto from the family land(adding gravel road, boat dock, plumbing, electricity).

What would be your savings and investment strategy for him?