I got a chance of running the rules.

I got a chance of running the rules. In order to manage the difficulty, I introduced a Wise NPC with healing magic(we almost had a TPK and my players had 1 or 2 hit points because if poor rolling). The rule of Wise cannot getting cure from magic became evident then, since it recharged all hit points of the sole magic user. What do you think about this rule? It worked out as a HP transfer, but how can I treat this forbiddance in terms of roleplaying?