Shortly afterwards, he lobbed into our heliport in a JetRanger, took on a full load of gas, put in 4 big boofy guys, 5 sets of golf clubs, and lurched into the sky for a golf course 3000' amsl. Amazingly, the machine got off the ground, and even got back again.
That's the sort of thing that is worrying. Not that he took more hours than anyone in the history of rotary aviation to learn to fly; that's OK - slow learners can be fine in the end. But that he had no idea of safety, weight and balance, and similar issues. Stupidity, lack of basic awareness, and other psychological factors (ie, being a loony) should prevent someone becoming a pilot - and they should be told.
But lack of aptitude? I don't know. Sometimes all it takes is identifying the problem. As a very new instructor, I was asked to fly with a chap who had over 40 hours and hadn't gone solo. Well, we did a circuit, and he was actually quite good...to start with. But as soon as he had to use the radio in the air, he got confused, couldn't think what to say, lost it, and we ended up about 1000 feet above circuit height. Next circuit, he did it again. So I did the radio for him, and he was fine. So we sat and had a long chat about him learning the calls, and knowing what possible answers to expect, and making those calls early to give himself time. Later, I did some private groundschool with him, as he'd left school at about 13, wasn't that bright, and couldn't work out what to do. All I did was show the relevance of some of the book stuff to what he was doing, and talk about learning in small chunks, and help him make a study plan. He passed the the first exam, and I lost my private groundschool job - he realised he didn't need me. And I presume he learned to use the radio and fly at the same time, as he eventually got his PPL.
All this chap needed was some intelligent instructing, based on HIS needs, not just on the books! He'd flown with loads of instructors, most far more experienced than I was at the time. Why didn't they identify the problem?
I daresay some people don't have the physical coordination etc to actually ever learn to fly, but if that's the case, they'll realise it themselves in the end...unless they're loonies as well.