My thoughts would be that she’ll not make it through the night in any case. Having another cause of death waiting in the future doesn’t mean the earlier ones aren’t as effective as without. That’s not how death works.
(And, actually, if she did somehow survive, the son caused her a guaranteed death date later.)
But of course it’s magic, so all bets are off unless you know exactly what the rules are and how to lawyer it.
https://en.wikipedia.org/wiki/Nils_Olav for that article in case someone wants it.