what to say to bf ?

he has ulcerative colitis/crohns since like 2015 so he’s had 2 colonoscopies in the past but it’s been a few years. i think since we been under alot of stress lately he is worried and paranoid when he goes for his 3rd on tuesday he won’t wake up. i want to comfort him him in some way because he’s just worried about it. any words of advice i could say to calm his nerves ?