Tomos William Iles-Spowart, 13, died in September at Colchester Hospital after suffering a fall.
An inquest held at Chelmsford Coroner’s Court heard Tomos had a history of muscular dystrophy, was looked after by his mother and attended school when he was able.
Coroner’s officer Sarah Lee said: “On the evening of September 24, his mother was assisting him with showering when the shower chair moved and Tomos slid forward off the chair.
“He seemed fine, but later that evening his condition deteriorated and he was taken to the accident and emergency department where he worsened.
“Despite CPR, he was confirmed deceased.”