He could get Landsknechts, they don't count towards the maintenance limit. Pikemen might make the issue worse.
It was the Landsknects that were the problem in this case; in real life they were mercenaries, in civ you have to be playing the Germans to use them.
Yeah, this time around, the Landsknechts did the uprising :D
They became available for other civs in BNW, if you had a certain Mercenary policy active.