Does returning a unit with Grim Apothecary to your hand detach the equipment on it?

Yes, returning a unit to your hand detaches any gear attached to it.

According to RiftJudge FAQ #9348, when a unit is returned to your hand (such as by the effect of Grim Apothecary), any gear attached to that unit does not return to your hand with it. Instead, the gear detaches and remains at the battlefield where the unit was previously located. Following the resolution of the ability, because the gear is now unattached and present at a battlefield, it will be Recalled to your base during the next cleanup phase (per Rule 452.1).