A lot depends on where the brain was damaged, if it involves any part of the left ventrical, it usually causes artery hardening in certain areas around the heart, but as it is his left side affected, it will be his right side of the brain affected, and vice versa, so better news.
Do try not to worry, many many people lead amazingly normal lives even after this, with just minor adjustments.
All the info you need is on the web.
I have damaged left ventrical, part missing/mishapen/irregular, plus fronm part of brain left side missing, but there is NO outward sign of this, other than terrible memory for faces, that I see "out of context".
My gf had a stroke at age 3-4 years old, causing here partial paralysis on left side with cubitta fossa syndrome(arm) and maralgia parasthetica(leg), but she's gets about ok, can run 1 hour on treadmill!!
I had my first MI, myocardial infarction, heatr attack some 2 months ago, was quite exciting really, just got put on more bloody medicine as a result, but have found the most awsome "medicine" ever, not a prescribed one, everyone can buy it, and it is f*****g awsome, I would not beleive it could do what it's done, it's truly amazing and 100 natural, and not that expensive either.
tabetha