Good Morning Doctor, Im From Mumbai. My Father Is Having

Good morning doctor,
Im from Mumbai. My father is having diabetes for the past 12 years. It was well under control. The readings were around 90-110 in the morning and around 160 post lunch. But for the last one month his sugar readings are high. Actually, he was hospitalized for 1 week , before 20 days, bcos of heart problem. From the day he got discharged , his sugar readings are high. its about 160 in the mornings and around 270 , 2 hrs after lunch. He was taking Glimer 2 mg for past 8 years. it was ok.

But now doctor added another Glimer 1 mg before dinner . Even after taking one more tablet , his sugar is high , the same 260 - 280 post lunch. Doctor could you please suggest what other tablet can be used to reduce his sugar levels. We are really worried. Thank you.