I'm so glad he did call. Would have been nice if he'd have told you that when he first saw you...since I'm sure he knew you'd have liked to have known...but some people just don't work that way. He might have also been waiting to see if you were going to bring it up...who knows.
But yes...that's a big step. I know you may not want to broach this with him right this minute, but you need to be on the account too. I don't even bring that up because of knowing his activity...but for the sheer sense of it. One of my best friends had her husband pass away, she had a REALLY hard time of things because her name wasn't on utility accounts, credit cards, cell phone bills etc. We all hope nothing drastic ever happens to our loved ones, but "IF" they do....having both people's names on the accounts is MUCH better than just one.