Boyfriend fainting twice after day of heavy drinking, should I be worried?.?

My boyfriend (who is in this late 20s) went drinking with his buddies from 3pm to about 8:30pm and had about 10 beers. Then went to use the bathroom around 3:00 the morning after and fainted waking me up and then fainted again when he tried to stand up again. I had him sip some oj and he seemed ok after that. This Practically frightened the living crap out of me. But as for his drinking habits he will usually have one or two beers depending on how he's feeling, and will once in a great while drink heavily, should I tell him to see the dr? I actually drink way more than he does and have never fainted during or after drinking so this is a little concerning to me. Or maybe his body isn't used to the sudden heavy drinking. Idk