Abdicating was no issue for Helena, but her royal household would be completely removed from power.
After all, there was no successor at all, so it meant either the complete dissolution of the Royal House of Norway, or they somehow borrowed a king from other constitutional monarchies.
That was common before the second world war, as most European royals were distant relatives. If one lineage was fading, they just had to send a distant relative over as successor.
But as foreign relations cooled