Adam's wheelchair accessible van

Adam was diagnosed with a regressive neurological disease aged 2. He was a bubbly little boy who was walking and eating and babling words before he began regressing and his muscles and limbs began giving up on him. He lost his ability to walk aged 3 and as the year's went on he is now unable to eat normal foods or sit or do anything he was able to do before exept smile and bring joy to our hearts :) Adam is now 6 and has grown out of his special car seat and unfortunately he isn't get any support in his seating wich leaves adam unsafe and uncomfortable. His wheelchair is 25kgs and I, his mother and primary carer have had to lift this heavy chair in and out of a car boot for 3 years now. Adam is in desperate need of a wheelchair accessible van where he can sit in his chair through travel with the support he needs and safety required. This will help in the future as his needs grow, his wheelchair is upsized and for other future needs as his condition regresses in time. This will help a mother save her back from the constant lifting of a 25 kg chair (and a lot more heavier upsized wheelchair) and the lifting of our growing adam into and out of a car seat for good. Any support big or small is highly appreciated. The cost of a brand new van is double this amount but we are looking for a second hand van that can get a family through the daily trips and constant appointments to the hospital and back.