Good luck, the more you relax the quicker all the little things will come together.
oh if he has started clothes sucking, take any toggles off cords in hoody type tops, as he might chip a tooth or manage to eat one, I just use to take the cord out, and buttons on sleeves.
Try not to use the word "don't", as that make it irresistible to do the action, go for lets do this ....
I use to say, oh dear, your top is wet, and quickly, positively change him/them into a new one, or they get use to sitting in soggy clothes and they stop noticing,
So if you change them, they think , oh it wasn't nice having the soggy top, this one much nicer, eventually they decide getting changed is a bother, easier to not get ones self soggy in the first place, once they stop every now and then they revert to clothes chewing.
It's always a long process, but if handled gently goes faster than if tackled
it's quite common especially in children who have like your son had early extra action,
It's just self comforting, so important to them.