For temp QT
you can do the winter koi method and put him in a rubbermaid container with areation/filtration (or areation and daily 50 percents)
but even if he recovers he is not going to be able to get away from that pleco adn he'll get sick all over again. He'll appreciate a lil salt and unheated water after his ordeal anyway.
But I think you picked up a separate Qt
yesterday, huh?..ack , I am slowin down.....