To be more precise I mean a kind of mocking sympathy where the person is like "Aw. You poor thing.." but it's pretty sarcastic.
I can't find a single word with the meaning you want. A common two-word phrase for this concept is "mock sympathy", which often goes along with the phrase or hand gesture of "playing the world's smallest violin."
For single words, the only terms I can think of are ones that refer to sarcasm in general, rather than false expressions of sympathy in particular: scorn, sarcasm, mocking.
For fake sympathy I'd suggest "Crocodile tears"
https://en.wikipedia.org/wiki/Crocodile_tears Wikipedia Crocodile tears (or superficial sympathy) are a false, insincere display of emotion such as a hypocrite crying fake tears of grief. The phrase derives from an ancient belief that crocodiles shed tears while consuming their victims.
For meaning the opposite of what one is saying: "ironic"
Irony | Define Irony at Dictionary.com dictionary.reference.com/browse/irony Dictionary.com Irony definition, the use of words to convey a meaning that is the opposite of its literal meaning: the irony of her reply, “How nice!” when I said I had to work all weekend.
Is the word you're looking for 'patronizing'?
This sort of remark is closely associated with the term:
deliberately impassive in manner
I suppose the delivery can be dripping with sarcasm, but along with, "you poor thing," you could deadpan, "Do you think I should call an ambulance?" So in that, light, deadpan is what I associate with this sort of mock sympathy. You deliver the words, but not the emotion.
if it's overdone (not necessarily sarcastic, but exaggerated, insincere, disgusting, fake) it could be called
- cloying sympathy
pretending to feel something that you do not really feel, or not meaning what you say.