It's an amazing amp he'll love it, the app won't work on the 100 it's only for the air (wireless)series, but you can plug it in via USB and use the tone studio software which gives thousands of presets etc and is an amazing tool for deep editing , also recommend picking up the GA-FC footswitch to be the perfect partnerWell just bought the boy a BOSS Katana 100 MkII for Christmas, it's his first proper amp, and since he had his new Mustang he's found a love for playing electric.
Hope he'll enjoy it, and hope I can understand how to help him set it up.