Further to Jimmy’s recommendation, before you speak to an experienced strata lawyer, organise a log of events:
What happened
When it happened
What the tenant did; what your son did; what you did; what the strata manager did (or didn’t do) etc
Include copies of emails, letters and any notes you have from your son, the tenant, the strata manager, servicemen etc
If you can get a letter from a doctor as to the deleterious situation in the unit, then that’s a big fat feather in your cap
You must tell the lawyer your story with as much evidence to back your allegations.
One more thing: Jimmy says that if the OC agrees at mediation to do as you want, then get it in writing. Having been there done that, I did get it in writing and the OC never followed through. Amazing! They knew I’d have to go to NCAT to get anything from them (and I did) but they also knew I would have to apply, rewrite my documentation etc and NCAT would not hear the case for at least 2 months from when I filed. Often closer to 4 mths.
At NCAT I got the order I wanted, but not the $202 application fee reimbursed by the do-nothing committee.