Marines do welding!
They do "I" level weld repairs at AIMD's both on land and shipbord, and even some depot level stuff at NARF facilities on all the aircraft and helicopters that they operate.
The work side by side with Sailors, They receive advanced training at both Cherry Point and Jax at least as far as I remember.
Get certified in an aerospace process (GTAW) before talking to recruiters... Then make sure the advanced aerospace schooling for the welding he loves is in his
CONTRACT BEFORE HE ENLISTS.
If he does not have the romance of aviation in his heart and wants to do structural welding... Join the Navy CB's
BTW The MOS for Marine Corp is Aircraft Welder, 6043
http://www.alamy.com/stock-photo-us-marine-lance-cpl-william-sutton-prepares-to-weld-a-ch-53e-super-129767734.html