My son was the same. Very cuddly child and after puberty that disappeared and doesn’t like to be touched. I also have a 5 year old so 16 and 5 both autistic boys. Very different. My oldest was always shy but my youngest is of course the complete opposite and talks to everyone. He has to say hello to anyone he lays eyes on and some people are not interested in talking to him and he’s completely oblivious. Hell just start reciting the script to his favorite videos verbatim and that’s how he communicates leaving everyone very confused lol. Meanwhile I can’t remember what I ate for breakfast.

My youngest recently asked me “what’s wrong” with his big brother because he’s “always angry” and it left me dumbfounded I didn’t know how to respond so I said he’s just different from you and some stuff is harder for him. I asked big brother to tell him he’s not angry or mad with little brother he’s just in a bad mood about something else and he refused to say that and just said “leave me alone” which is code for “I’m about to have a meltdown” so I left it at that. Little brother doesn’t know what it’s like to have a cheerful sibling. Bc big brother is always angry about food choices, house temperature, homeschool, chores etc. He’s always very grumpy but when I ask him he says he’s fine as long as hes “left alone”. He refuses to discuss the future, getting a job, or not being able to, or friends. But he’s going to be 18 soon and I’m already applying for SSI for him because he will lose health insurance and all that other stuff like I will probably need to be his guardian because otherwise he won’t make it. It’s extremely stressful and socially isolating.