Father had stroke shortly after Flu Vac, I have questions, need help finding answers

My Father Had blood drawn at the VA & recieved flu shot in his left arm last thurs.. He developed bad bruising and swelling in the area. Apx 12 to 18 hrs later he developed some tingeling and odd feelings in his left arm which was still very sore.. 24 hrs after the shot he developed a low grade fever, and a few other flu like symptoms. Apx 48 hours after the shot he stared loseing feeling & movement in his left arm and progressivly the left side of his body. On hospitalization he was told he had had a light stroke.
After much testing including brain MRIs etc No cause was found for the stroke. Dr says he looks very healthy. HE is almost 80 has slight diabetes and has had some heart problems for many yrs but did not have high blood pressure or any other contributing factor they could find. HE is back home now 3 days after the stroke and getting around with a cane or walker.
My questions are. Does anyone know if an injection site hematoma can break loose and cause this type of a stroke?? Some info I read seemed to point that it could but I really cant find anything. It is now 6 days after the shot and blood test and his arm is still purple and sore.
Has anyone heard of this type of reaction to the current flu shot. I am not sure which one the VA in TX is giving.
I make be shooting in the dark but I think We ought to check out the possibilities so if anyone has info or knows where I should look please let me know. Thanks very much Tweet