[GiorgioG]

My son hasn't been formally diagnosed but has/had some similar issues (he hates fireworks/loud noises, picky eater (not great given that he's a type 1 diabetic)), and also used to have trouble falling asleep on his own. Everyone and every situation is different but I think it's important that you don't stop exposing him to these triggers - introduce them slowly and be persistent. Some people take longer to become comfortable (emotionally) with something that's new/"scary"/unfamiliar with. My son (11 now) still dislikes fireworks, but he no longer is terrified of them. He tolerates them (he used to cry on the 4th of July, etc.) Despite not enjoying loud sounds he loves to hear his favorite NHL hockey team's goal horn/siren and all the noise that comes with attending a sporting event. Six years ago we took him to a soccer game featuring his favorite team at the time (Real Madrid) and while there were fireworks at the beginning and the end of the match he tolerated them because he got to see some of his favorite players.

We were at the beach last week and he was afraid of going into the ocean. I didn't push him to go further than he was comfortable with (compared to our older daughter who is fearless). I encouraged him to take a step forward with me and just stand there. We were out there for probably more than 45 minutes and by the end he was waist deep and laughing. There were a few hiccups (a few waves came in that caused him to drink some water) that made him retreat some, but he got over it.

Picky eater - this was me as a kid and my parents did me a disservice my not making me try foods "I didn't like" (even though I'd never really tried many of them). We make him try foods he claims not to like and gradually his tastes are changing (more slowly than we'd probably like, but that's ok.)

Falling asleep has been an ongoing issue that ebbs and flows. It ultimately comes down for him to learn to quiet his mind and body. Occasionally he'll have something irrational that he's afraid of. We'll have a chat, I may sit with him while he falls asleep and over time he realizes that he's safe/fine/etc.

My neighbor had a similar situation with their teenage autistic nephew who came to live with them. Rather than tip-toe around his fear of loud sounds, my neighbor forced him to learn to cope with them. He made his nephew help him hold some lumber that needed to be cut with a chop saw (they're loud if you're not familiar). At first he cringed and didn't do what he was supposed to. He told him "<name> I know you're scared, but if you don't do this I can get hurt. I know you don't want me to get hurt, so I need you to do this." The next time he did job and they kept cutting the lumber until he figured out how to cope with the noise. His nephew is now an adult in his 20s and is the lead singer in a heavy metal band.

In the end, be patient, persistent and don't stop exposing your child to these things.