Suggest Treatment For Low BP After Kidney Transplantation

My husband is 83. He is a kidney transplant patient, has atrial fib, and diabetes 2. He s on coumadin. He fell on Wed outside, scraped his nose, hand and elbow and was woozy. Ambulance took him to ER. He had xrays of head, pelvis an leg (he was complaining of hamstring pain). xrays were ok. At hospital his bp was 140/82. Today he got up late and hadn t eaten yet and it was 11 a.m. He was going out and was dizzy. I took his bp and it was 64/34, pulse 51. I sat him down and gave him breakfast. 20 min later, his bp is 62/37, pulse 47. We re going to wait about a half hour and I ll take his bp again. If it stays low, should I call his physician and get him to hi office? Thanks so much, Barbara