An example of how healing would work;

If you wanted instantaneous healing:
mob
verb
Heal(mob/M in world)
M.HP = M.MHP//Where HP is the mob's current hit points and MHP is the mob's maximum hit points, which you should have defined as a var somewhere in your game.

If you wanted random healing(Like from a spell)
mob
verb
Healsome(mob/M in world)
var/heal = rand(1,M.HP)//Where HP is your mob's current hit points
M.MHP += heal//add the randomly generated value to the mob's Maximum hit points.

You'd have to change the vars to the ones you have defined specifically in your game, and if you want these verbs to work only on those in view, change it to "mob/M in view()" within the parenthesis.