My daughter had hers out at a similar age (20, maybe?). It's VERY important that he keep drinking cool to cold fluids. Not only does the cold temperature help temporarily numb the pain, but keeping the throat moist will inhibit any hard scabs from forming, a big source of the pain after the first couple of days (especially when swallowing). If I remember correctly, he should try drinking something like 8 to 16 ounces ever hour. You might want to check with his doctor or a nurse in the office for guidelines on this.
Pills are difficult to swallow. Any chance of getting him some liquid pain med? As others have said, smoke will increase his pain.
My daughter had a really hard time with this for the first week or so. As for your younger sister, tell her it's not bad for younger people and is more difficult as people get older, like your brother, and that how you deal with the recovery (proper use of medication, following doctor's orders, remembering to drink cold things & eat popsicles and such even when you don't want to) will make the recovery much easier. Tell her it'll hurt a little, but smart people who do the right things hurt less for a shorter period of time. Or, as my dad always said, if you're stupid then you suffer. She can learn from your brother's experience that listening and following directions can be the smart thing to do.
Still -- no matter how smart, this hurts. Patience, cold things help -- and good for you for hiding any kind of smoking material
Oh, BTW -- alcohol doesn't count as a "cold drink". The alcohol burns like crazy, as do the bubbles in sodas. Go for juice, iced tea, smoothies, etc.
Hang in there -- both of you.