fall apart

Collapse, break down, either physically or mentally and emotionally. For example, This chair is about to fall apart, or After his wife died, he fell apart. For synonyms for the latter usage, see come apart at the seams; go to pieces.

The verb has 4 meanings:

Meaning #1: lose one's emotional or mental composure
  Synonym: go to pieces

Meaning #2: go to pieces
  Synonyms: break, wear, wear out, bust

Meaning #3: break or fall apart into fragments
  Synonym: crumble

Meaning #4: become separated into pieces or fragments
  Synonyms: break, separate, split up, come apart