friend is missing

I’m in a situation where all I can really do is sit and wait. my bestfriend/on again off again boyfriend (were off at the time) went missing. he will be 18 in roughly two months. he is homeless at the time as he had been put in a “crises intervention shelter” which is a fostercare shelter and is basically a jail. no phone calls no leaving the premises no internet basically your totally secluded, his dad is an insane freak who almost killed him at one point in time and his mom is a heroin addict. he ended up running away and lived on the streets of portland. he calls me daily and he hasn’t called in the past couple days and no ones seen him or heard from him. I actually went to portland and searched high and low for him just to end up with nothing. I’m worried because he has both a scarr and a tumor on his brain and if he doesn’t take his medication he goes into seizures and they will kill him. I’m not sure if he has been able to get his medication while on the streets. I’m really not sure what I can do…at all…I feel like really I’m not even sure how to explain. he’s such a close friend I just can’t lose him. cops are involved his case worker is involved. I’ve really done all I can. called all his friends who live in portland. I’ve done everything…I just want to be able to do more.

any tips on calming down or helping anymore?