How many points on the kite does that bridle leg attach to? Does it fan out and go to more than one? In other words, how many points on the sail does it support? Does it affect the way the kite flies? If there's no adverse effect on the kite's performance, I would just fly the kite as it is and wait until it parts. It doesn't support more than about 1/8th (perhaps less) of the pull, and will probably hold for much longer than you would imagine. What I'm saying here is: If it ain't broke, don't fix it. Even when that leg breaks the kite will probably still fly quite well.