I'm sure this bug got fixed before, but now it's back.
When Guy Bourgeois has 0 MP remaining and sees wounded faction mates, the "Healing" tab is invisible. (He has no healing items on him). Once his mp rises on the tick it will reappear. Lay on Hands doesn't use mp.
* The tab is not closed when it reappears
Lay on Hands not working at 0 MP
Re: Lay on Hands not working at 0 MP
There's a fix for this for the next patch.