Hmmm... if he absorbs the heat from it, would it still be a hot gas?
Yes, because plasma is freakishly hot. He might be able to absorb it down to safe levels, but it still would be hot.
Actually, being hot isn't a key of being plasma. The heat makes it INTO plasma, but cold plasma is possible - it's the ionization of the gas that makes it plasma. So, theoretically, even if it were cold, it would still be a threat due to the ionic energy. So, I guess you could even add electrical damage to plasma.Plasma's some dangerous stuff.