The 19-year-old had recently woken from a coma following a near fatal road accident when burglars broke into the first-floor flat on Hala Road where he had been staying and ransacked the premises.
The offender or offenders stole a computer games console as well as several games, and items of jewellery belonging to the teenager including a valuable, 26 inch, thick, gold chain, with oval and round links, with a pattern on alternate links.
The 34-year-old owner of the property was staying with her son in hospital at the time of the break in on June 3.
He had suffered serious head and back injuries following the collision on Ashton Road, Lancaster, on April 29 and been in both the Royal Lancaster Infirmary and Royal Preston hospitals.
DC Paul Donnelly said: “This is a dreadful crime made all the more despicable given the circumstances surrounding it.”
Anybody with any information is asked to contact police on 01524 63333 or Crimestoppers on 0800 555 111.