Frequent meltdown

my 26 year old son has recently had to move back in with us as he was getting targeted by the local youths where he lived on his own. However, he is now having meltdowns on a daily basis, is very aggressive and threatening. He needs his own space, when he is in his own space he has control and his meltdowns are often maybe only 3 or 4 a year. Why is it so difficult to find housing for adults with ASD/Aspergers.