He was speaking of a method of trying to clean the inside out. Not specifically a disinfectant, but was thinking along the lines of some drug being able to do something similar. Look, it was worded poorly. I get it. he's going to have to take the "L" for poor phrasing. But the guy is smart enough to know (and you know) that you can't inject Lysol in the body. Of course, he then came back with qualifier and said "you all are doctors, you all need to look into that" or something like that.
I mean, there are plenty of things to beat Trump up on, but this is just the media seizing on a poorly phrased remark and running to extremes.