Hi bwest09,
Welcome to NeuroTalk.
I'm very sorry to read that your fiance has PCS. Serious memory problems as you describe would depend on the severity of the injury. It isn't something that I've seen posted very often but some of the members on the PCS forum (link below) may have more input.
Make a post on the
Traumatic Brain Injury & Post Concussion Syndrome Forum
take care.