You are not doing your future daughter in law (or son in law or whatever) any favours by helping your son too much.
I dated a mummies boy. He expected me to do all the house work but I could “tell” him if and when things needed done.
At which point he would complain the football was in and he’s busy so will do the hoovering tomorrow or whatever. And never did it.
He never learned the skill of working out what needs done and when by using his own eyes. I had to be the ‘mum’ and tell the man I lived with when to do what. I didn’t sign up for that responsibility. (What’s wrong with his eyes/memory. Can he not see the carpet needs hoovering? Why’d it have to be my responsibility? Do my boobs somehow mean I am blessed with extra housework super powers? No I don’t think so!?)
So he never felt the need to work out when to do this load or that load as certain things would be needed for work next week, or there wouldn’t be enough drying space for the sheets if I do the white wash today too etc. Or how it’s murder when you come home from work knackered and have to start housework or you have plans and it doesn’t suit and I should have planned my week better....
He needs to learn to work his housework round his social/TV/compute gaming life too (ie no housework on Saturday when the footballs on so I’ll do it Friday to leave my Saturday clear).
So give him his own basket and tell him that you are no longer doing anything to do with his room, bedding or clothing or ironing or dusting his room as he needs to do his own stuff so he knows how and learns to take responsibility.
Split the household chores for the living room, bathroom, kitchen, garden etc up on a whiteboard in the kitchen so everyone knows what needs to be done and all share. You may want to do more if your dp and son work full time and you do part time. Or you may not. Your family and you can decide what fits the bill.
Just don’t make your son a useless as my ex. Whom I would still have been with had he not been so lazy and inconsiderate round the house! I feel sorry for his new gf!