Maybe you could ask him to help you problem solve and give him a choice for delivery method such as just swallowing fast or mixing with some food to mask taste (applesauce has always worked for us).
In addition, we always had better luck with Tylenol Meltaways rather than liquids for fever reduction.
He is 20 mos old. The verbal reasoning is just not there yet. I think that in another year, this will work. We can tell him this will make him feel better in a few minutes. And he gets it. And he wants to feel better. But his emotions trump his intellect.
