suits are a bit tricky IMO. For our wedding, my husband got fitted for a rental tux & day of he went to pick it up and it was all wrong! not even close to fit! Ended up wearing a black jacket and pants from the closet and looked great! I think men sometimes get it so easy.......but he also does not like to dress up.
Nordys and Macy are very good, and the Rack often has great deals. but I don't think they are near you.... A high end consignment shop can also be great, good prices and quality, if that is something he would consider
Since he has pretty average measurements, you might get lucky online with ebay. I know it can be risky, but if you take good measurements sometimes the deals are amazing. For a looser fit, I would avoid some of the designers that call their fits "modern" (Kenneth Cole comes to mind) as they might be to narrow for his liking