Thank you for the query. As per the history, your father (aged 60yrs), with a BMI of 25.4 kg/m2, has been suffering from type 2 diabetes since 8yrs. In this context I would like to know what is his status of blood sugar control (FBS, PPBS, HbAic) and what medication regime he has been taking. Fever and weaknes, in an elderly diabetic gentleman may suggest Urinary tract infection (specially those with poorly controlled sugar status and prostatomegaly). I would advise you to get a Urine for routine examination done, incase his fever is persistent. Altered bowel habits (loose motion/constipation etc) is common in diabetic patients due to diabetic gastroparesis and short intestinal bacterial overgrowth (SIBO) syndrome. You can give him oral rehydration solution (ORS-Electral) if he is having profuse diarrhoea since it will replenish his elecrolytes. I would also advise you to give him probiotics (eg lacobacille sachet) which are helpful it this situation. Ceratin blood investigations are advised like TLC/DC (to rule out infective cause of diarrhea), FBS/PPBS/HbAic (if not done in 3 months), urea/creatinine and Urine Routine examination. If an infective cause of diarrhea or UTI is detected antibiotics need to be given. A strict diabetic diet is advised, which should not include refined carbohydrate and carbonated beverages. Saturated fats are to avoided. Since diabetes produces a catabolic state, adequate protein intake is advised. Presently, he will benefit from the intake of curd (since it is a natural probiotic). I would suggest you to take him to his treating physician so that a thorough physical check up and vital parameter measurement can be done. Hope this helps you.