should i tell my mom my brother is in jail?

[hello kitty]

this is the situation. i have an older brother & sister. we grew up with our dad cuz my mom left us and started new family. although we still spent time with her throughout the years during weekends n holidays it was not the same. my brother who is 29 yrs visits her on the wkends but there is not a bond between them like their should be. now my bro lives with our father. last thurs he got busted for serious drug charges. posession of controlled substance, intent to distribute cocaine and cocaine manufacturing. he's still in jail bc bond is too high and we lawyer working on what can be done. so my sis keeps telling me not to tell my mom but shouldnt i tell her? my mom keeps calling me prolly to ask me if i heard from my bro and i don't wanna answer. his phone is cut off which is sometimes not unusual but he has not gone to my mom's house like he usually does every other sunday so that's weird and so...shouldn't i tell her...i mean it's her son and even though they don't have a close relationship. shouldnt' she know??? please advise...i'm torn!
my mom is pretty distant from us as far as getting involved in our affairs so it's not like she would do anything to get him out. right now he not getting out cuz bail is too high 15k. so we have to wait for court date or till probation officer can offer maybe a rehab sentence... otherwise i believe he can go to jail for up to 5-10yrs....
i'm semi close with my mom but my bro; he's my bro and we grew up together all of our lives. and she's the one who left. on the other hand i knw my bro has a drug problem n he needs help...