Tell him to see if he can get on a DEP (Delayed Enlistment Program). He can make up any reason he wants to apply but the one that seems most likely to work is personal problems. In most cases the DEP needs to be done pre-enlistment but I've heard of people getting into a DEP due to personal problems after enlisting but before reporting to a duty station. He may be able to buy some time that way. When I joined in 1971 I had a wife and baby so I went in on a DEP for an extra month to get them moved in with family.

https://www.thebalancecareers.com/the-delayed-enlistment-program-dep-3332701

Tell him to see if he can get on a DEP (Delayed Enlistment Program). He can make up any reason he wants to apply but the one that seems most likely to work is personal problems. In most cases the DEP needs to be done pre-enlistment but I've heard of people getting into a DEP due to personal problems after enlisting. He may be able to buy some time that way. When I joined in 1971 I had a wife and baby so I went in on a DEP for an extra month to get them moved in with family.

https://www.thebalancecareers.com/the-delayed-enlistment-program-dep-3332701