I have two with ASD and selective mutism

I have 2 with ASD one 18 and my son 15 they also have selective mutism & social anxiety my daughter goes to college  she only has two friends and one of those have moved to another town she never goes out and she stays in her room she gets depressed i really could do with some help at home for my daughter like a support worker or something but don't know who to ask.

my son stopped speaking in 2014 and to this day i don't know why he stopped going out he won't go to school he stopped eating and washing his hair was all mated he would sleep all day and be awake all night.He was sectioned on 2015 and was in hospital for nine months he was diagnosed with ASD & selective mutism and was discharged June 2016.He started to go to a medical education school with only a few students but now he has stopped going again he still won't leave the house or his room and still won't speak or look at anyone he's awake all night and sleeps most of the day 

I'm at my wits end and really worried he doesn't seem to be depressed he's just got no motivation to do anything I'm worried he's going to make his self really ill i need help