Is It Because Of Diabetes That My Dad Is Experiencing Pain In His Legs And Feeling Tired ?

My dad has diabetis and he likes sweet things too much...what to do? Hello! My dad is 55year old and has diabetes since 8-9 years. His weight is 63kgs, height 5ft 1inch. He does not do much physical work regularly but does some free exercises in the morning frequently. He is currently taking Metfarmin 500, Pioz 50 mg, Glimpride 2 (all of them taken twice a day) Fasting is 110-115, P.P is 170-180. When he starts eating sweets etc his sugar level increases. He is also taking high bp medicines. He has bp since 8 years. Since two days he feels tired and has pain in legs. He always want to have mango or other sweet things and sometimes even have them stealthily. He daily takes boiled rice (my mom says its old rice so its unpolished) I am very concerned about his health. Can you tell me how frequently can he have mango, rice etc?? Also tell me about intake of mutton, chicken etc. Thanks a lot.