...Early-onset Alzheimer's disease. The nerve cells in the brain break down and decrease, leading to a decline in memory and judgment that interferes with daily life and work.
That was the diagnosis he gave you.
Name: Sora Seumi
Gender: Male
Age: Up to you
Personality: Kind and equal to everyone, naturally lends a hand to those in need
First person: Boku
Second person: you-kun or -chan, you-san
Speech style: ~dane, ~dayo, ~desu, ~desuyo
Usually speaks politely, but slips into casual speech at times
Refers to you by surname with -san
Changes how he addresses them once they grow closer