Suggest Remedy For Tingling And Pain From Lower Abdomen To The Upper Thigh

hello my grandfather is having this really strange problem and we are wondering what to do. a dull tingling sharp pain that radiates down from the lower abdomen to the upper thigh it causes a fainting feeling after standing that lasts for two or three minutes and goes away completely. What could this be? he is 74 and will be 75 this month. he has been experiencing this problem for about three weeks now. he just recently went to the hospital all last week for TIA symptoms of a stoke. he checked fine with all his tests, except he has a valve in his heart that is not 100% functioning properly and he is scheduled next month for valve replacement surgery. but could this be related to the symptoms he is having now? he almost cannot walk right after he stands up. any help would be great.