I suppose it would be going too far to say that he is on the job market right now, but I'd like to help him out.
You can mention this, but you have to do it jovially, with a light touch.
I did this with a panelist who I knew well. Of course I got her permission beforehand.
"Her new book,
Religion and Power in New Jersey, just issued by New Jersey University Press, is an innovative treatment of our panel's topic. It's on display at their booth downstairs, isn't it, Dr. Smith? And if your department is hiring this year, you could be fortunate enough to secure Dr. Dr. Smith as your new colleague, since she's on the market! You'd better tender a very good offer, though!"