My Son Is 19 Yrs Old And Has Been On

My son is 19 yrs old and has been on Actemra IV infusions for about 4 yrs for his juvenile rheumatoid arthritis. Since he has turned 18 he hasn't been getting his monthly infusions on time. Sometimes he skips a month.... He has the attitude that he doesn't need it...BUT as his mother I know how important it is for his body. He was diagnosed w/ JRA when he was 3yrs old. I'm wanting to know what effects this has on his body when he skips this treatment?? He works 4o hrs a week and lately has been very tired looking :(