Hello, Sorry to hear about your son. Well, to answer your query, I would like to tell that expectancy of life cannot be predicted because we do not have much detailed version of history. Also, no one can say what will happen when science has its limitations which you might be aware by now. As your son is autistic and have a seizure disorder, I would like to ask you, how active is your son. Is he able to move around, is he able to walk, run, climb, etc. Is he having any kind of chronic cold or cough issues, etc? If your son is able to move around then maybe making him walk a lot can help improve the lifestyle and the expectancy of life can be improved. Based on the physical examination and also some lab findings we can figure out how to overall improve his lifestyle and avoid getting him into illness more. Medicine department is symptomatic and rests the body heals on its own. Also, for kids with autism, we need to work out with a team of autistic rehabilitation but to say this, I am sorry, we can expect big changes in his overall lifestyle change. We can provide ease but by now I think you must be aware of such things. Sorry once again if any word of mine was felt bad. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Jay Indravadan Patel, Physical Therapist or Physiotherapist