What a deal breaker.
But there are quite a few hubs that can be converted from QR to through axle, just by changing the end caps. So he could upgrade the fork without changing the wheel.
However a 110mm boost need some shims and is clunky.
Yeah I'm well aware of that, having just gone through the process of buying budget wheels. The problem I see with that is if you are shimming to use a non-boost wheel in a boost frame or fork then you kind of defeat the purpose of boost. The whole point of boost is that it puts the spoke flanges wider which allows you to build a stronger wheel with less flex because the spokes are coming in at a wider angle. If the flange width isn't changing then you're not getting the benefit of the boost wheel.
They actually have a 100mm x 15mm thru axle version. So I could just get that.
EDIT: updated the build list
That would be a better option but you'll then have a boost rear non boost front unless you order the non-boost version of the FM10. Nothing at all wrong with that, I almost did, but I decided that if I have to get new wheels anyway, as I do to take advantage of the 27.5 + size tyre profile, then I may as well go boost as well.
Not sure what country you are in but in Aus the 2nd hand market is flooded with Roval traverse 29 wheelsets for a reasonable price, if you're Stateside I would have thought you would pick up a set of them very cheap. Have you looked at places like Pink bike? I wish the DT Swiss were as cheap here as they are in Europe.