@Nancy88,
This meaning of 'nerve' here in your example, Nancy, is this;
==============
McMillan Dictionary
a rude attitude, usually shown by behavior that makes other people angry
==========
In definition/meaning #3 from M-W, below, note how this figurative meaning of 'nerve' moves from a positive meaning, found in 3a and the first part of 3b, to a negative meaning, found in the second half of 3b.
=======================
M-W
3.
a : power of endurance or control : fortitude, strength
b : assurance, boldness; also : presumptuous audacity : gall
=====================
Sahadja Yoda [sp??] has illustrated for you, in a real life situation, that "he" is acting the meaning found in the first half of 3b. As you can see from reading the replies, most everyone thinks that "his" reaction is that of the second half of 3b.
This thread has provided an excellent example showing how the nuances of a word can change dramatically according to who is viewing the situation.