See 2scents reply. For Trump or any politician to demand the FDA should approve or disapprove a drug for any reason is very troublesome as it would add a political dimension to medical decisions. The FDA has to made medical decisions outside political concerns. This has long-reaching implications for safety in medicine that go well beyond the current situation.
As an aside, a doctor can prescribe HCQ without the FDA doing anything. The issue here I understand is limited supply of HCQ (hence various restrictions placed on prescribing it) and questions about its safety. Not saying anything about whether the dosage that Zelenko uses poses any real safety issues or not, but there are safety issues with HCQ and several studies using HCQ have been stopped due to safety issues.
Going back to the evidence issue here about whether this works. I discussed a bit above why I think results Zelenko and others have with this might not mean anything much. Without a proper study it is difficult to know what to make of all this. There is a study that is starting or has started already that is looking into this as a preventative treatment with medical workers (as Dr. Zelenko recommends), but initial results are not expected to be published until a year from now. Perhaps if there are results that really stand out in a short-time they may provide an update sooner, but we are likely talking about a few months at minimum, not weeks.