My roommate is allergic to washing his dishes.

I’m a (M21) and I have 3 roommates & I have this little nagging persisting issue. Mind you these dishes have been here for the past 4 weeks- and it’s specifically one individual who will cook and just leave everything dirty, it was worse than this until me & my other roommate about 6 weeks ago decided to wash them for him, but he keeps doing the same shit and I refuse to wash them, and shouldn’t have to. I even got Cascade Plus Pods to help lessen the issue with this particular roommate yet he still doesn’t wash, and now the longer they stay the more mold & bacteria arise.

And before you ask, yes we’ve told him to wash the dishes. Yet he claims it’s not him, when obviously we know- since the others use paper plates. How do I handle this?