This treatment is being suggested on bases of the information provided. However I would like to examine & investigate your grand father in detail. -Control  Hypertension, Diabetes or  metabolic disorder, if there is any. -Any way it may be tried, --. Dolokind Plus (Mankind) [Aceclofenac100 mg +Paracetamol 350 mg] 1 tab. OD & SOS. X 5 days. --. Caldikind plus  (Mankind) 1 tab OD x 10 days. -(You may need help of your local doctor to get these medicines.) --. Fomentation with warm water. Let the part not be exposed to cold. --. Sleep on a hard bed with soft bedding. --. Keep  a pillow under the feet. --. Avoid painful acts & activities. -- .Do mild exercises for  foot and ankles. --.(Take help of physiotherapist or you can visit my YouTube channel Dr. N. C. Gupta and watch 'Me & My Yoga' and 'Yoga Simplified'. https://youtube.com/channel/UCPEQc6B1ywzwin048JSu6rw --Do not ignore, let it not become beginning of a major problem. --Do ask for a detailed treatment plan. Kindly make sure, there is no allergy to any of these medicines. --For emergency treatment visit nearest hospital. --Wish your grand father a quick recovery & good health. --I hope, I have solved your problem to your satisfaction.  Dr N C Gupta MS (ortho)

As no other details are mentioned give him paracetamol 640 or tab Ultracet for pain.