Party was determined disabled after signing a mediation agreement that left the party destitute
Party is determined mentally disabled at the time the document was signed
Party was without representation
Party attempted to alert judge pro se
Request was deemed "moot" by judge
Other party retained all property, bankrupted joint debt and the disabled party is being held responsible
Disabled party signed poa to other to act on behalf and then other bankrupted the property leaving disabled responsible

If the person was determined by a court of law not to be mentally fit to understand the legal action, then their guardian ( court would appoint them a guardian to care for them) could file suit to over turn prior legal action proving they were not mentally able to defend thierself.

But merely having mental issues, and some mental illness that does not effect this ability to represent theirself will not have a bearning