and buying a Dragon is an expensive option too if you don't want it otherwise.
If you have a balanced army (especially with a neutralizer like a Nazgul) and you play it well and separate out his Heroes one at a time then you can probably start turning your games into wins. But it sounds like he picked the point level because he's setting his own sweet spot for the army lists. Much higher ( like 500 ) and you'd out number a force loaded with three major Heroes and have a much easier job on him.
If you play with LoME rules and scenarios then he's going to change pretty quick. He won't find it very easy to win most scenarios with those, except perhaps Contest of Champions or To the Death. Just random roll the scenario and you'll find he's going to be pretty disappointed when Take and Hold or High Ground comes up.
Personally though, I'd just "beat" him by saying "no thanks. Your armies are pretty boring. I'll play someone else".