Aneurysms and mood swings

I am in a stressful situation over the last month, my sister started dating a guy who says he has a brain aneurysm and i cant stand to be around him he is rude dosent seem to like to be around other people and says stupid stuff. My sister is always telling me to lay off that he acts like this because of the aneurysm. My father had an aneurysm 5 years ago but did not have anything like my sisters bf. i dont know what to believe anymore he says he cant take the medication that was given to him by his doctor because he is allergic but isnt there anything else that can help he aslo told my sister he was going to japan for something for his aneurysm ??? does anyone know anything about japan and researches on aneurysms or treatments they offer? deeply concerned about how he is treating my sister and i wonder if the way he acts his from having an aneursym.

im no pro but he can have it done here, like the rest. A aneurysm affects each person different, try to talk to him and he may talk.