flake out

verb

1. To fall asleep from exhaustion or intoxication; to lie down.
2. To flake or be flaky: to prove unreliable; to abandon or desert someone.

   “John said he could drive me to the airport, but then he flaked out on me, and I had to call a cab at the last minute.”

3. To crack up or break down; to have a mental episode; to behave eccentrically.