Commanding Demons (or anyone else)

The act of commanding demons is different from the sorcerous acts because it is not a ritual: roll the sorcerer's Will vs. the demon's Will (the strengh of its binding can enter into the equation as a bonus for the demon if the command directly opposes demon's relationship with its master). (Cf. Issuing Commands)

"Stamina" and "Will" are not "body" and "mind."

Stamina and Will are both physical and mental phenomena. When your character looms physically to intimidate someone, that's Will. When your character calls upon memories of childhood abuse to draw upon hate in order to heft that portcullis, that's Stamina.

Stamina = impact on, influence over physical motion.
Will = impact on, influence over personalities.

Both draw on whatever physical and mental reserves are necessary for these effects. [1]

Using Will to get back on your feet.

When a sorcerer succeeds in their Will roll to temporarily regain Stamina (or some other score), they regain the score they were trying to get back simply by rolling any degree of Victory. For example, if they have a Will of 5 want to get a functional Stamina of 3 this round, they roll 5 dice against 3 dice and get all 3 dice for Stamina if they get any victories at all on the 5 Will dice.

The sorcerer gets one action at the restored score (ignoring ongoing penalties), then goes back to suffering whatever lasting penalties they were suffering (the temporary penalties that would have affect that action have now elapsed). If the sorcerer is still in the hole Stamina-wise, there's no reason they can't do a Will roll again next round.