High sugar level. Vaccine by any chance?

My father who is 66 year-old, 10 days before he was peeing more often (every half an hour) we ignored thinking it's normal since we installed AC in his room recently. Later last Monday he got his 2nd dose of covieshield vaccine post that he was having weakness/tiredness in his body which is post vaccine side effects so we gave good amount of fluids juise/ glucon d but still he was not recovering so on Friday we checked his blood sugar lever at home it came 556 ( apparently which is quite high) Now we are consulting with a doctor locally some test were prescribed by him and zavamet 50/500 But still he is not feeling any better. What should we do next? Is it due to vaccine by any chance ? PS he is on BP medication already