How emotional!

Your friend's reasons examined:

#1

"There is no testable or reliable means to prove that a god exists. Science has already explained many phenomena previously attributed to a god, and they don't see that progress stopping."

A. What is the compelling need to prove that a god exists? To be a true atheist, there should necessarily exist a compelling need to prove a god does not exist. I see no compelling need for either.

B. What specifically has science explained that was previously attributed to a god, specifically in modern times? We're not talking about what the ancient Greeks thought caused thunder. What recent notions about a god have been dispelled by science? Science can neither prove nor disprove the existence of a god.

#2 Not a valid cause to turn atheistic. Just because god doesn't always meet our expectations of what we expect of him doesn't mean he doesn't exist. Parents don't always meet our expectations. We don't always meet our own expectations of ourselves. We sometimes expect from others that which we cannot or will not give to them.