The pills were sold on the black market and were extremely hard to come by.
They made you forget things Most people used them to for the bad memories – abuse, trauma, pain. Kieran used them differently. He used the pills to rewatch TV shows for the first time. His fifth time watching Star Trek for the first time. His eighth time watching Doctor Who for the first time. Crime shows had great rewatch value when you could make yourself forget who the murderer was.
He didn’t use them too often; if you weren’t careful you ended up forgetting more than you wanted, and Kieran planned to hold on to most of his memories until the end. But since he didn’t have long left, he figured he might try to recreate some past joy.