Leo has FOXP1 syndrome which affects the development of the brain, impairing learning and speech.
He moved to the care home in 2021 after his needs became too great for his parents to cope with at home.
He is now 18 and his care is fully funded by the NHS, but he was previously under the care of Cumbria County Council, which was disbanded in 2023 in an overhaul of local councils.
Josh MacAlister, Labour MP for Whitehaven and Workington, who led a review of children's social care for the last government, said moving people away from their community "disadvantaged" vulnerable children.
CEO of children's charity Become, Katharine Sacks-Jones, said distant placements could be "disruptive" and "traumatising".
Cumberland Council, which was established last year, said it had improved children's services by achieving a "good" Ofsted rating.
Labour council leader Mark Fryer said: "The previous county council was either inadequate or requires improvement for almost 20 years and in 18 months we've turned that around to be rated good - a huge feat."
The council also said it planned to build new, local children's homes.