Lucifer has had an interaction with Milyn and it was actually one of his first genuinely positive experiences here on the turtle! He would not be interested in just letting her die.

That said, he wouldn't jump in and mess about while the healers are doing their thing and is more than happy for them to succeed. However, if necessary, Lucifer's ability to bring people back from death, 'complete reversal' did remain intact, per the mods.

Using it would be completely dependent upon all other sources failing and, of course, the opt-in of Milyn's writers. ;)