Welcome to HCM,
Your father is having UTI with E.Coli which is common micro organism for UTI but it is notoriously resistant to many drugs some time.
Please note some times drug resistance
is seen in lab but drug is effective in treating infection in patients.
Please complete the course of injection as suggested by doctor, this drug Magnex is not known to increase blood sugar level,and his blood sugar is in diabetic range as he is not known diabetic please follow diabetic diet at present and control blood sugar with short acting insulin
Once UTI is controlled and then you can repeat FBS,PPBS and HbA1c to know exact status of diabetes
Please also get a Ultrasonography
to detect any obstruction to urine flow which is common in this age like BPH and Stricture.One can see with Residual urine.
Once injectable course is complete then oral suitable antibiotic may be given for followup.
Please take opinion of Urologist
Hope he improves soon.