My nephew has it. He is a bit more high maintenance than most 5 year olds. But he has his special toys that calm him in an episode. They got an emotional support dog. Compression pressure along with therapy helps as well. As for my sisters sanity. She does the best she can to prevent the meltdowns but sometimes she can’t

Find outlets for them in their space. It's helped my son tons and he's in therapy 3 times a week now