The wanting to sleep and the irritability could be sobriety OR drinking (and hiding it). When I was newly sober my sleep schedule was all out of whack, I was tired all the time. I wasn't particularly irritable, but I know a lot of people are.
The not wanting to drive doesn't ring true to me, though. Could be he was drinking or it could be he just wanted to skip the meeting that night. Either way, you will find out soon enough if he is still drinking. Shouldn't be a long wait.