My husband’s GI Bill for college

Hello, my husband was deployed during Persian Gulf war. He believes he has access to some GI Bill funds for college because he never used them. Google is saying that he only had access to those funds for 15 years after he separated from the military, which for him was 1991, but there always seems to be grey areas. Can someone please confirm whether he might have benefits and/or who to contact to see if he does? Thanks!