What punishment will work on my brother?

ok so I have a 16 yr old brother.. and my mom has no clue what to do about him. he's failing, he doesnt care about anything, he doesnt fallow any rules. but u cant punish him cuz he doesnt care, she takes away his phone, grounds him, takes away his bike..he doesnt care he will walk, nothing works for him. what can my mom do to shape him up she just wants him 2 come home at curfew and make decent grades.