Does throwing it at them work?
I would be worried that the potion would deal bludgeoning damage before applying the healing effect (knowing that this is just Early Access). Or the opposite where it heals you first, only to damage you for the impact afterwards. I haven't tried tossing a potion at one of my characters yet, and am reluctant to find out (don't want to hit them while they're already down).
A right-click option "administer" would be useful to give you a 5ft radius to apply the effect to an ally as an action; as LazerOfDensity suggested.