He's kind of right

There are some FR and 6-max regs who suck horribly... HORRIBLY at HU are still profitable playing it, because you can just table select for the biggest donk and make a profit.
But it is a very different game. I think there's very little you can say about it in a nutshell because it's so incredibly opponent dependent...
Just play some HU sng's and switch to cash once you're comfortable.
Swings are big... I'd recommend 50-100 BI especially if you're just starting or suck at HU.

But still... table selecting is obviously very important. If I can't spot a very obvious leak that I know how to exploit withing 25-50 hands, I'm sitting out and waiting for the next guy.
I don't sit out very often though.