Bad business

I need some feedback. My husband owns a tint shop. A guy came in three months ago looking to learn to tint but not a job. Over the last 3 months my hubby has taught him how to tint and pays him but the guy won’t quit his day job and won’t commit to working for my husband. Now, he says he’s ready to work alone on saturdays at the shop. The shop is typically closed on Saturday. So my husbands going to pay him. He hasn’t filled out an app, we don’t know his SS or anything. My husband is just a trusting person, me not so much. Am I wrong thinking he needs to at least get the guy to fill out an app and get a commitment from him. I just feel like he’s a liability. Idk