Was Paul suffering from Downs ?.

I know its a show and the character was written that way, but hypothetically,
a person that stupid and asocial can't be correct in the head.
Time and time again, Paul shows a serious lack of intelligence and a behaviour
that goes against any social normality rules of behaviour.

For instance, on episode 8 season 3, the guys helps paul move for 8 hours
and still paul doesn't pay for the coffee at the bar afterwards.

A person acting like that in real life would find himself short of friends
and close ones really fast. I think a person like Paul would be better of
at a mental institution for a few months or years, or at a home for mentally
handicapped people.