This gentleman is in his early 70's! He has knee problems.
His seat is too low and likes it that way. At least on
the Schwinn it will only go so far down, unlike the
MTB he has, he looks like a grasshopper riding a bike.
And yes, he never stands on the pedals.

I have torn down the BB and cleaned and inspected
ever thing and they look fine, but in a week or two
they are loose again.

I think he is messing with them, although he says not.