If this was in NSW, and the roof was genuinely fragile, the OC could order its repair or replacement within the restrictions of its by-laws in relation to its appearance.
However, Queensland has this two-tier strata system relating to townhouses, duplexes and the like so I’m afraid I don’t have a clue what the overall Body Corporate’s rights or responsibilities are. All our state strata laws differ but Queensland is another planet.
For some reason this problem reminds me of the Bonzos’ My Pink Half of the Drainpipe. Listen and smile.