So you think selecting flap is a good idea with a wing in that state
Yes, FWIW (not much), I think it was.
There was no reason for the pilot to believe that the operation of the flaps had been adversely affected. He could see that the damage was to the outboard section of the (famously strong) wing.
ie To the 13 feet (approx) section beyond the folding mechanism.
See:
If his belief turned out to be wrong he could, as Henry says, have taken appropriate action.
a rather reduced wing & no aileron
Where do you get the idea that he had no aileron?
He would I suspect have been experiencing a great deal of buffeting, and have been acutely aware that he might lose it altogether, but the (shortened) aileron protrudes beyond where the mainplane has disappeared. The outboard hinge departed with the lost section of wing (about 4 ft), but there were still two of the three hinge points remaining.
"it would be all too easy to select in a hurry to get down"
I have no reason to suppose that he did anything in a hurry following the collision. From the reports I've read elsewhere, he appears to have assessed the situation and his options and then landed safely.
I would not have criticised him if he'd got out in a hurry; he opted to stay with the aircraft.
BTW, I'm sorry you regard my comment as cheap; I thought it was valid. I admit to being influenced by some of your previous comments in this forum, which IMHO have been quite extraordinary given that you are not a pilot.
Yes, I know you've sat in with some top pilots.
You could sit in a garage for hours but you still wouldn't be a car.
FL