I'm worried about my sons health

hi everyone, I'm stumpted on what I can do for my autistic son, who is now 13 years old. lately he's been wiping his *** on his bedroom carpet and walls as well as other surfaces around the house and I need some advice on how to tackle this problem. I'm not only worried about his health and wellbeing but also, my daughter is only 6 weeks old and I don't want her becoming ill over it as my sons personal hygiene problem is so bad, he won't wash his hands or do a poo in the toilet unless I tell him to, which he gets angry at me for and lies to me all the time. We currently have a picture routine hanging up in the toilet to remi him on what to do but that doesn't seem to be working.  Could anyone suggest a solution to our problem that works, please help