Sister raising her teen brother needs advice

Tl:dr: brother moved in with me after suicide attempt, making friends but telling them lies about himself and parents using me as the bufferMy teen brother attempted suicide a while back and after a stay in a psych hospital he tried to go back to school but couldn’t do it. He does not have a good relationship with our dad so he moved in with me (3 hr from our Mom), changed schools, and seemed to be doing great here.I take his phone every night-every other night to check messages and make sure he’s not expressing suicidal thoughts to anyone. Last night I found a long message to a new friend at new school and it is almost completely fabricated.He starts with his birth. He said he was born one month early (not true he was born the day after his due date) and was messed up when he was born. He said he was a born with a physical disability and is legally disabled (not true-he was born with some delays but had physical therapy and was doing fine). He said his whole childhood he was pushed to the back-attention-wise. He said our uncle killed him self and that caused our dad to become an abusive alcoholic (not true-uncle died from DT’s withdrawing from alcohol and while Dad did drink a lot he was never abusive). He said he moved out of state with our mom and kids immediately started bullying him, beating him unconscious, shoving his arm into metal on a locker and cutting him until he was faint from blood loss (Mom says while he was bullied it was never physical). He said he began dating a girl and all they ever did was drop acid, smoke weed, have sex, and he would get drunk every day (Mom says there is no way any of that is true).Now the suicide part: In his message he says that his suicide attempt involved him cutting his arm and drinking a bleach/detergent mixture so he would bleed out while he died, then our mom walked in and found him covered in blood and unconscious and took him to the hospital. This is NOT true. While he did cut his arm it was a week prior and he drank 1/2 cup of detergent and immediately started throwing up and called 911 himself. My mom was at work and she met them at the hospital.Why is he lying? If he moved away to get a fresh start then why is he telling this new friend all his skeletons? He has always been a very VERY quiet kid and I’m trying hard to get him to talk to me and I’ve bought a book on depression and I’m having him do some exercises in it but he does go to counseling bi-weekly.My parents are the worst communicators ever (with each other). They hardly speak to each other and instead they will tell me, “well he’s been raised like this for a long time so now you have to change that”, or ask me if I’ve talked to him about all this. I don’t mind to talk to him about things but I am so stressed with trying to raise him, since I have 2 small kids, husband, and full-time job of my own. via /r/Parenting http://ift.tt/2GhGjkt