just about any good bootfitter can make a boot 3-5mm wider, per side, so this should not be a huge deal. nothing will fit him (or most people) off the rack, with out some mods to it.
I'd start with a good local boot fitter (good list at the top of this forum) and if you need to go the dale boot/ strotz option so be it, (they are great, but not always that close to you, so adjustments, or replacement parts might be hard to deal with)
lange concept is 104, salomon mission a VERY wide 104, and most other companys make a wide option.
again, seeing someone local, and that is good, is a great starting point