Have people you don't know give him a fairly minor ass whoopin' every six months for a couple years, then once a year for a long time. Make sure you always know where he is. Hire someone to take tons of pictures of him in different places for a long time. Periodically, send him a picture. Try to have him photoed in places where he probably feels very secure. Make that motherfucker turn his worthless, pathetic head to look over his shoulder wherever he goes. For a long time. However, this is probably not the most healthy way for you to deal with this. And by the way, DO NOT let your sister know (or anyone)...that is often not good for her healing either (although I'm no shrink). Another alternative is to find the largest, most well-endowed gay man and pay him to...you can guess the rest.
I am terribly sorry for what has happened, and I truly wish you, your sister, and your family a speedy recovery.
God bless you.
-Chimborazo
PS - To any LE types who have a problem with this, do your moral duty and FORGET what you just read.