I would translate your sentence as

Funny notion of friendship you have there!

In fact I wonder where you got the translation “drôle de” as meaning “incredible/terrific”. “Drôle” means “funny”, amusing, and is is quite often used sarcastically, just as in English.

Drôle can have two meanings depending on the context : the most common one is “amusant, comique”, and a less used one is “bizarre, curieux”. I would translate drôle in this sentence by “weird” or “strange”.

This second meaning is often implied by the use of “un drôle de” + noun.To answer your question, not only “drôle de” can be used sarcastically but it is specifically used to suggest a sarcastic meaning.

Un homme drôle : a funny guy /
Un drôle d’homme (or better : un drôle de bonhomme): a strange guy