"arborvitae are next to weeds. They don't require much care at all.
I
just trim mine once a year to shape them, and if it has been a bad
winter I know the snow off. No watering, no fertilizer. Quick
growing, nearly ideal plants. "

I'd agree with that, for the average US climate. Of course, if he's in
AZ, that's another story. They will need to be receive water at least
once a week for the first year though.