Anyone have an idea?

My little brother (who is not so little now) is 22 years old. He was diagnosed with cerebral palsy (although I somewhat disagree with this diagnosis), Wolfe Parkinson White Syndrome (a form of irregular heart beat), Cleft palate (not including the lip), undecended testes and he has been tube fed since the age of 2. His mind is that of a young adult, but he is quadrapeligic with some movement of his arms and legs (he loves Wii & other video games), but he is quite verbally impaired and uses a computer to talk for him if people cannot understand him. He has had multiple surgeries, the last one was about 7 years ago when he had a rod put in his spine to help his scoliosis (which went back to the way it was before within 2 years). He is slowly declining and we as a family have chosen not do extreme measurses although he is going for tests next week just to see what is going on. His latest symptoms include, choking on his secreations and wounds not healing. I know this is the start of the end, but my question is does anyone know an approximate life expectancy for someone like him? We know he is not going to life forever, but we hope and pray that this process does not drag on and he doesn't suffer. Any ideas from any health professionals, or anyone in our situation as well?