Rykymus
Line Up and Wait
Only because he's your FiL, I'd try to talk it out with him. This is going to come up again and again. You need to make him realize, that while his thousands of hours in big jets is an impressive accomplishment, and undoubtedly makes him imminently qualified for the job he does, he is not more qualified in the area of flying small GA aircraft. It's as simple as that. If he's a normal, intelligent person, he'll see the logic of your argument. Try phrasing it in an analogy of some sort, one that isn't aviation. It's like a plumber and an electrician. They both work in construction, and they both string networks of things through homes to make stuff flow from source to destination. But you sure wouldn't want a plumber doing the electrician's job.