Hello, thanks for the query to H.C.M.C.
drugs , you mentioned in your query usually causes fullness in stomach, mild hyper acidity, bloating
etc and at this time age of your's father is 79 yrs , hence due to old age , these symptoms aggravates , that's why your's father feeling excruciating pain in abdomen.
2 nd reason is that your's father is a known case of type 2 diabetes
, so more prone to pain due to general condition.
Consult a physician and get in blood examination for blood in stool
Also discuss about haemorrhoids ( for passing of blood).
As the query is about low sugar level at once give 1-2 spoon of sugar.
Usually blood sugar level falls in diabetic patients and they know it very well because of their disease.
Regards Dr. HET