the man towards whom...

[navi tasan]

1) The man you were rude towards is my friend.
2) The man towards whom you were rude is my friend.
3) The man you were rude to is my friend.

Are all correct?

I find #2 natural and #1 a bit strange although #3 sounds fine to me.

 

[Tarheel]

All are possible.

Opinions on what's natural can differ.

 

[emsr2d2]

#3 is certainly the most likely in BrE. #1 is correct but less likely. #2 is very formal and would sound old-fashioned these days.

 

[Tarheel]

If somebody was rude to your friend, what would you say?

 

[SoothingDave]

3 is natural. Normal people really don't use "whom" much, if at all.

 

[jutfrank]

Are all correct?

You're not asking about grammar, are you? I assume not, but after years of reading your questions, I'm still not sure.

If you're looking for a sentence that sounds more like real English, I'd suggest:

That man you were rude to is a friend of mine.

The pattern you seem to be wondering about is this: be rude to someone