Just use dettol, and you don't have to worry about it ever again.
Can you get him a pop up laundry bin that way it's a space saver when empty and he has his own basket. Primark sell them for about £5
A grown MAN shouldn't be told things, he should use his common sense 😒 but even after being told he is still ignoring it, i would be raging too. My partner worked in a care home during covid and he washed his things separately. I feel for you, especially with wee kids.
Can you have two separate wash baskets maybe?