Work Apparel?

One of the people at my table seems to be taking our casual dress code a little lightly. He just started coming back into the office and every day his shirt seems to be getting a bit smaller and smaller. He may have shrank all his clothes during Covid or he might have gained a few. He also sometimes wears a jean jacket which is really not business casual. How do I tell him that it may be better to be more work appropriate and presentable?

PS: I like jean jackets but when you walk around the office looking like you're from the Outsiders its a bad look