I started working for my dad when I was about 30. Did my 4 year apprentiship with him. He then retired and I bought the business. It has been a tremendous asset having someone to ask questions, bounce ideas, etc. His background is motors and controls. We worked good together. Sure there were some differences, but it worked out. I enjoyed the time spent. We discussed everything from work to church to family.
My wife still gets tired of every family get together becoming a meeting with plans for the latest project on the table.
If you can work together, I say go for it. But have the discussion ahead of time that if working together begins to go south that it's over. It's not worth losing a relationship over.
Reno is right. Help him all you can.