Amazingly, ambien has had a similar effect for a small group of patients, returning them to consciousness for hours at a time after months or years of coma
https://www.nytimes.com/2011/12/04/magazine/can-ambien-wake-...
https://www.nytimes.com/2011/12/04/magazine/can-ambien-wake-...
Also GP if you check this - what are the downsides of gabapentin your relative was trying to get away from? I thought that was a fairly benign drug, even for long-term use.