I think the issue is the circle of friends. Had he been off a dating site - anonymous, basically - then sure, cut off. As is, the situation calls for a little diplomacy.

Most people are uneducated about ED. Even some doctors are, in my experience. Also, a lot of people in general tend to be grandiose so if he is, his lack of knowledge combined with the grandiosity could have led him to believe that he is the God-send who will cure you.

So let us give him the benefit of the doubt.

You need to establish very firm rules of what is acceptable. The rules are:

1) you are awesome "as is" with no modifications and only deal with guys who accept and recognize that you are awesome "as is" with no modifications

2) if he thinks that there is something imperfect about you, see (1) above.

3) optional as it involves too much detail-the above are more high level:

a) you will weigh yourself whenever you see fit wherever
b) you will tell him how much you weigh only if you think it appropriate and he is not to ask
c) your hair style is strictly between you and your hairdresser; if you ever decide that you could somehow benefit from this guy's opinion on your hair style, you will then ask him for such an opinion; you do not need unsolicited feedback
d) three strikes law applies