Is My Diabetic Father’s Weakness After A Positive Coronavirus Test And Typhoid Diagnosis Serious?

Hi ..! Thr my father is 61 yrs old & he is a diabetic patient. He took 1st shot of covid vaccine after 10 days he started feeling sick & I consult doctor & found typhoid. I have also done myself antigen test for Covid of my father , found +ve . Right now he is so weak but no difficulty in breathing, no fever or headache,Oxygen level is also balanced . And doctor gave him antibiotics, vitamins,paracetamol, cough & cold tablets. So is thr is something serious issue..?