I recently learned about Harvey Friedman and he seems to be quite a peculiar figure. Friedman is a real mathematician who founded the programme of reverse mathematics, which I think sounds very interesting. He's also known for the TREE sequence. However, he has also appeared on crackpot-friendly Curt Jaimungal's podcast and seems to agree with a sensationalist article written about him some years ago. If I understand correctly, his current work is focused on bringing the incompleteness of mathematics to the forefront in a way that mathematicians won't be able to ignore any longer.
For those who have been familiar with him, what are your own impressions? Do you know what the general opinion of the mathematical community is of him, if they know him much at all?