He did. And he recently did a video talking about british research, which, having adjusted for socio-economic factors showed that the darker the skin colour the more likely the person would be to develop complications. His point here was that, dark skin impedes vitamin d generation.
It should be noted that while he does have some qualifications due to being a nurse and a nursing teacher, he's a Doctor in Philosophy and not in any medical/science field. It doesn't dismiss his claims per se but I still think he's using his Doctor title in a somewhat misleading way in this Covid19 context where a lot of people seem to think he's actually a medical doctor which he's not (edit: and this can be easily verified by just skimming through most comments on his videos which praises him in that regard).
His PhD is in medical education, so I don't think it's fair to say it's not in a medical or science field. His online bios are clear enough about this, so I can't see how he's misleading anyone.
This is kinda true, though he has earned the right to call himself a doctor, and I dunno if he should have to constantly have to add "though not in medicine!" Maybe he should? I don't know if "misleading" is the right word. He does seem to have expertise in the nursing field he's teaching FWIW, but yeah I researched him several months ago and found his linked in page which said the doctorate is in philosophy.
"Dr." for 'doctor' is the continental titulatur for finishing and successfully defending your doctoral thesis, thus attaining your doctorate. PhD is one of the US-variants of a doctorate. Reading 'doctor' and thinking 'MD' for 'Doctor of Medicine' is a mistake, although understandable when talking about medical issues. From Wikipedia I understand that f.e. in Canada MD is an undergraduate titel.