stroke & heart

My brother just had a stroke (blockage of oxygen to the right side of his brain)... he is 61 & 1/2 years olds... they just checked his heart (angiogram) and we were told he has a "hole" in his heart and they will have to do surgery to fix it... what came first???  the heart problem or the stroke???  did the heart problem cause the stroke because there wasn't enough oxygen to the right side of his brain because of a possible "clot" from his heart?... or was there not enough blood pressure thru that area of his brain because of the heart problem?... or did the stroke cause the "hole" in his heart causing it to be damaged enough so they have to do a "repair" to avoid another stroke?...

Thank you so much if you can answer these questions...