I think the military service is great for his career and life.

Many college grad just work a dead end job in starbucks for 4 years.  Transition from military to civilian might take some effort. But doing it at 30 is better than doing it at 40.

Another truth about lawyer is that it is a service industry with relatively short engagement and lots of client turnover.  You alawyas have to meet new client, present yourself and ask him to trust you.  Any distinction from other normal lawyers is helpful in the business.  I know people with M.D., Ph.D. and went into law.  Their resume is better than just a regular guy.  Military background is the same way, it makes his resume stand-out.