Your son is doing much heavier style music than I do, so I don't know if this would work, but I use drum loops from
www.smartloops.com What I love about them is they are real drums played by a real drummer, there are countless fills that come with them, and there are lots of variations of basic beats.
In addition, they are very affordable.
Probably not a lot of Meshuggah style loops out there, but for more rock and pop oriented material, they are great. Incidentally, I like the loops that came with PT's 8, but there are almost no fills or cymbal hits in the drum beats, so you pretty much have to use one loop an entire song (not that it hasn't been done, for example John Mayer's Heartbreak Warfare).