Talk to General Physician on Low Blood Sugar Or What?

Asking it for my brother, His age is 26 weight 140 kgs, he has been taking coversyl 4mg and byscard 5mg for his bp for 2 years, he is also taking calc 1000 plus by himself, he is non diabetic, he has a bad sleeping routine and eat junk food. He also has anxiety issues He was doing brisk walk tommorow. Suddenly he felt need of peeing and extreme hunger and low shakiness in his hands and legs he went to shop eat icecream and he was fine. He checked his sugar it was 97, 107,98 after eating icecream. Now his fasting sugar is 91, 90 He eats late at night only and miss breakfast and sleeps in the morning around 10 am. Only sleep for 5 to 6 hours. Please let us know what it could be.