Hi Doctor's, I'm Worried About My Husband. Just A Brief

Hi Doctor's, I'm worried about my Husband. Just a brief health history... He is 63 with numerous health issues. Diabetes, congestive heart failure, neuropathy, PAD, heart & leg stints. This past year has been very challenging with an Arterial left leg bypass, and the worst....SEVERE GI BLEED from "both" ends supposedly from prescription nsaids. Was given "8" pints of blood with a BP of 50\20 and survived this. This was 6 mths ago.
Since then, occasionally he seems somewhat jaundice. Now he is having this "awful foul smelling" belching that actually smell like farts!! It's so bad I thought it was my dog!.. I know this is NOT NORMAL and would like your opinion as to what you think this may be. He has an appointment with his GP next month and usually has labs every 6 mths.