The rules for an Aboleth’s Enslaved feature relate largely to combat situations. What we are having a problem with are the limits of what a charmed person would do for an Aboleth.
The closest effect I can match this to is the spell Charm Person:
The charmed creature regards you as a friendly acquaintance.
I get the sense Enslaved is far more powerful then this charm effect. However, it is not distinctly explained what the non-combat effect of this is. Is this more like a dominate person/creature spell?
For instance, could an Aboleth convince an enslaved person to sacrifice themselves to raise a demon causing death to the individual, or to kill itself in order to hide a secret (for instance if captured or caught)?
I realise that causing damage results in a saving throw, but what about making the enslaved individual take an action that will probably be fatal before the victim can make its save?