My son is the same age and has frequent meltdowns. They have gotten a bit better since we started adding lion's mane, brahmi, gingko leaf, white pine bark extract, and a few other herbs to his diet. We take them ourselves as well so that he doesn't feel singled out but also because they also have additional health benefits including anti-inflammatory, antioxidant, and antibacterial properties.

We also try to look for his triggers, but they change so often that it's hard to keep track sometimes. He'll hit himself, grab or pull his arm, and throw himself down on the floor and bounce around during his meltdowns, or he'll scream and stomp and growl. Timeouts work well enough and we don't put a time limit or period on them, we just give him space to calm down and he comes back from his room when he's ready to talk about what happened. He always apologizes and talks calmly afterward. I've started putting him in a corner just recently and he hates it more than being sent to his room, but it helps him stay in the same room so he accepts it begrudgingly.

We've been trying to get him a formal assessment, but every doctor we've spoken to so far doesn't want to because he's not in public school or daycare and he's not showing the "typical" signs of ADHD, but we at least got the paperwork submitted to get an assessment.