Many of us could not survive without them.
I kid you not, in my freshman Crim class a student even had the nerve to watch porn next to me one day! If however he chose an inopportune time, gently and apologetically let him know that as much as you would love to have the discussion, there are other pressing things you need to sort out first and would need to take your leave.
Roasting your younger brother will kill his self-esteem.
He then goes downstairs, cries or gets angry or something, and then comes back up and just walks over to us like nothing happened.