My dear son's classmate who had the same condition as my son, went for chiropractic and after a yr of treatment, he is partially discharge now.
We wanted to get dear son a proper chair for him, coz at home, he is still sitting on the baby bouncing chair and is always part lying down. And his pram for outdoor use is not too suitable for him as he tend to always slide down while on it and not sitting upright. But the pushchair recommended by therapist are way way so ex, and we are not able to get a subsidise!!