My Husband Has Been Having Stomach Problems For About 2

my husband has been having stomach problems for about 2 days. he's 72 and has alot of health issues. heart failure is one. He is seeing a dr. in 2 days but his stomach is hurting so bad he doesn't want to eat. now he has diarrea. I have stomach acid reflex medicine for myself but am afraid to give it to him. it is omeprazole 20mg. He also has low blood pressure. what should I do for him? I want to help him and don't know how.