I would suggest he goes along to the forthcoming Holt's Auction viewing days and spend some time having a good look and play with a number of different doubles - there are plenty to choose from in good Wildboar calibres. Many, prticularly the Ferlach or German are built but small craftsmen type gunmakers, rather than big factories. Their quality is wonderful, but a smaller maker you may not have to pay too higher a price. I have had a good look at the new built over and under and side by side doubles coming out of Italy and France built on CNC machines etc. They are definately good value, but not on a par with a handbuilt rifle from a generation ago.
I have a lovely 7x65R / 16 bore combination gun built in Ferlach that I paid just over £1,000 for in a Holts auction three years ago. The rifle is very accurate, yet it handles like a fine shotgun. When (not if) I take it after boar, I will use a 173gn bullet in the rifle barrel and a slug in the top. If I was shooting running boar regularly I might spend a further few hundred Euro's on an Einstecklauf liner barrel in 7x65r to go into the shot barrel, but from what I have read a 16bore slug would be sufficient both in terms of punch and accuracy for the ranges required.
There are a few like it in the current Holts auction.