Hi, Welcome to HCM. You should have mentioned history of any past illness or medications your father has been taking, however I will try to help you. As diagnosed the swelling, pain and colour change of the fingers are due to obstruction in the blood circulation. Such a condition can be a complication of diabetic neuropathy, get your have father screening tests ( doppler ultrasound test ) done to study and detect the cause so that he can be treated at the earliest. The other reasons can be rheumatoid arthritis and other autoimmune diseases.It can be due to intake of medicines like amphetamines, ergot compounds sometimes beta-blockers also present with such symptoms. Your father should stop addictions like alcohol, smoking, caffeine or any other kind. He needs to be clinically examined by an expert and get vascular ultrasound and other required blood tests done. Help your father keep his body warm, wearing gloves will be helpful, soaking fingers in warm water will give temporary relieve by restoring blood flow. Pain relievers, anti bacterial oitment and antibiotics can help. Your father should not get injured in the fingers, it can result in pulp infection and complications. Hope my answer will help you. Take care.