quarter friend
1. A person that is there for others as a friend during tough times, crisis, and turmoil when others are not.

2. Someone others can count on to be an honest, loyal, reliable, and supportive friend.

3. When a person needs a friend and has nothing more than a quarter (coin) in their pocket, a "quarter friend" is the one they call.

4. The term is used in the song Quarter from Fuel's 2003 album Natural Selection.
Liz's friend moved away and won't speak to her anymore. Michael is there for her as a quarter friend to listen and empathize as she copes with the pain and sadness.