The lawyer is digging an even deeper hole for himself.
The HK CAD require persons issued with a medial certificate to report all injuries immediately.
Failure to do so is a breech of HKG CAD regulations, and thus fair grounds for termination.
Then saying he had a head injury associated with a loss of memory, that can result in a loss of a medical for 5 years to life depending on the reason to rule out epilepsy.
Did he declare that medical issues to the FAA when he worked for the airline in the US after CX ?