How important is the workshop? Can it be rescheduled? I'd be tempted to go with that option... because work is pretty un-important to me and I generally try anything to get out of work if I can

Otherwise yep I'd be going with option 2 as well. Why is he uncomfortable - doesn't know the other parents?

ETA - you posted while I was typing! If he gets anxieties about it... might not be fair to force him into it?

I think Nan could take him! That'd be fine!