MP constantly gets refreshed when fighting with the appropriate support. This allows you to have a little extra wiggle room with your HP. MP is not so important to have a really high amount.
Well if I was a guessing man I'd say that this is Vitrolants HP build, but why would you use Liq. Earring in HP build, so I don't know. Either way I'd bet as /nin he has around 1650 HP.