Does the “damage for disobedience” effect from geas end when the caster dies? [duplicate]

This question already has an answer here:

  • Do your spells end when you die? 1 answer

I have a situation where some NPCs were under the influence of the geas spell by a pair of Lamia. They commanded the NPCs to rebuild some buildings in a town to furhter the Lamias’ evil goals and to protect the Lamias. As a DM, I had set the clock at day 9 out of 30 when the PCs showed up.

Geas / Duration: 30 days
You place a magical command on a creature that you can see within range, forcing it to carry out some service or refrain from some action or course of activity as you decide. {snip} While the creature is charmed by you, it takes 5d10 psychic damage each time it acts in a manner directly counter to your instructions, but no more than once each day. {snip} You can end the spell early by using an action to dismiss it. A remove curse, greater restoration, or wish spell also ends it.

I also have, as part of the background, a set of graves of NPCs who tried to flee and died from 5d10 for not obeying the Lamia’s command under geas. (They can each cast it once per day, so can build up a small work force rather quickly). The survivor is aware of “if you disobey the Lamia, you die” problem.

The party slew the Lamias in a battle (despite a lot of misses due to mirror image on the Lamia) and also slew some of those who were under its effects.

But one of them survived, with 1 HP. The party also knocked out five other NPC’s who will recover soon. The rest of the NPCs protection the Lamia died during the battle. I do not think that being knocked out ends the geas: it’s not a wish, remove curse, or greater restoration.

If the party offers to take the NPCs away from the town and return him to his kinfolk, and the NPC goes with the party but does not first complete the task of rebuilding the buildings in the town, does the NPC take 5d10 damage?

Geas does not require concentration; I am unsure if the death of whomever cast the geas on a creature ends the spell, or if the compulsion continues until the spell’s duration runs out regardless of whether the caster is alive or dead. I suspect it’s the latter.