I'm confused now...how does that particular joke suggest people should lighten up? (Not trying to be difficult, but genuinely curious - I would never take it that way, but I often misunderstand things.)

OP - what the letter said about medications is quite clear, as LG points out. You only got the letter yesterday or the day before, right? Given that and that it's a holiday weekend in the US, he may not have gotten to deal with medications yet.

I would really strongly encourage you to not contact this guy under any circumstances. Now that you are not his patient and he has made clear he wants no further contact, what's to say he might not cause legal trouble for you if you try to maintain contact?