I have difficulty eating a regular meal, please advise?

my husband has been told he had a infection somewhere in his body after three weeks he is losing weight and can no longer eat savary (savory) food only fruit and cereals. he is a type two diabetic and he seems as if he is suffering from worry about what the doctors have said
can you advise me

Age: 74
Medications: asprin, omaprazal, tamzon, cardorvol,
General Information: i have arthritis in my hips kneens and ankels, I had a heart attack 10 years ago and three metel stents put in i have had no pain at all after the heart attack. i can eat toast ,breakfast ceirial, fresh fruit, bread with butter, but when it comes to eating a main meal i gag at the food. this has gone on for over three weeks.
it is worrying me and my nerves are becomming woundup.