If he is worried about traveling, he should get a passport. He will need a certified copy of his Birth Certificate and the court order showing the name change. When he gets his passport back in the mail, he can file the BC and court order in a safe place and use his passport as ID. I use my passport for all travel, it's easy to use and there is no question as to it's validity.
If he doesn't want to get a passport, his DL can be used for air travel, but he would need to bring all the paper work for a cruise.
Honestly, a passport may be a big expense, but they last 10 years, they are easily replaced if lost (MAKE 2 copies of it, one to keep with you and one to keep at home), and can be renewed very quickly.