How did Maedhros stay alive?

[Inziladun]

Originally Posted by Galadriel55

~The Words of Hurin and Morgoth, COH

This quote supports what Nerwen said. However, even as the greatest Ainu, Morgoth is inferior to Eru, and Eru holds the power to give or take im/mortality. It's not up to Morgoth to decide to make a human immortal until he got what he wants?

Or is it just withholding the death, not making one completely immortal?

I don't get it.

I've understood that to mean Morgoth basically froze Húrin's body in that particular moment of time, while Húrin's conscious mind remained awake and aware. Morgoth didn't permanently alter Húrin's potential for mortal death, he merely postponed the aging process.

It's not so incredible, really. Sauron accomplished something similar with the Nazgûl, making death unattainable to them while they were under his will. Of course, when Sauron's power was lost upon the destruction of the Ring, his hold over the Ringwraiths was loosened. Had Húrin still been there when Morgoth was defeated in the War of Wrath and forced into the Void, Morgoth's power over Húrin would have dissipated and Húrin freed.