Complications after ostomy removal

Hi all,
My father (69) had ostomy reversed early May, but he recovers so slowly, he has had fever and high body temperature even before reversal. Lack of appetite, frequent fevers, got lots of antibiotics, but temp. wouldn't go away, sometimes too frequent stools. Recently in ER they noticed puss coming out of his wound, gave some antibiotics that didn't help. To make things more complicated, he has urinal catheter since his first surgery last July.
Can somebody, please, share their experience with similar complications with ostomy reversal and how did they manage to recover? I am extremely worried because surgeon scheduled him for rectoscopy, he is suspicious of another cancer because of the puss.

thank you

he didn't have ct but mri in March, it was ok, also blood markers were in normal range.

urine culture was done, and he was on antibiotics pretty much all the time since first surgery or at least one week each month.


they didn't look for c. diff, but they gave him injections of amicacin, that strongest antibiotic that is given for c. diff, but temperature won't go away.
this is all happening outside of us.
Thank you for reply.