Trump has downplayed the virus since the beginning and yes he’s given what I would call quack medical advice. I.e., he’s weighing in on issues that are (a) deadly serious, (b) he knows less than nothing about, (c) he has enormous power to influence and has a presumed trust because he has access to more and better expert fact and opinion than almost anyone (notwithstanding that he squanders it).
He denied the facts to downplay the virus. He ignored warnings from his advisors. For some weird reason, he made the question of one particular drug, hydroxychloroquine, a personal matter rather than simply a medical question. He suggested bleach or light “inside the body” should be explored. What else do you expect from the guy who literally altered the observed path of a hurricane, with a sharpie, then lied about having done so.
On masks specifically, until recently he has sent his loyal supporters - who he himself said would still follow him even if he shot someone in the middle of Fifth Ave - a confusing and mixed message on masks. This is not unlike the dog whistles he blows to provide aid and comfort to his racist supporters ... sure my advisors say wear a mask ... BUT ... I’m not wearing one, and you don’t have to wear one at my rallies, and maybe they don’t work ... wink, wink!
Trump says face masks are 'patriotic' after months of largely resisting wearing one