If respect is to be shown so casually to any one who demands it, then it is merely a freebie that would not be treasured. If one expects another to be deferent because one is older, then something must be wrong.
It doesn't matter that one is a smoker or drunkard or had messed up his life and the lives of the people around him.
It doesn't matter that he's rude or uncouth. It doesn't even matter if he respect you.
All that matters is he's family and therefore, must be respected. One is obliged - perhaps even forced - to respect.
What a profane idea. Just because respecting people carries no price does not mean it has no value.
The very act of respecting must be respected.