Bill Howard, 79, was found with serious head injuries in St James Street shortly before 2pm on August 28, 2021.
Emergency services attended but Mr Howard was pronounced dead at the scene.
A post-mortem established the cause of death to be fatal head and chest injuries.
John Swannack, 59, of St Leger Court, Accrington, admitted murder at Preston Crown Court on January 12, 2022.
Swannack also admitted two counts of theft and three of fraud in relation to other vulnerable people, police said.
He will be sentenced at Preston Crown Court on Tuesday, March 15.
Speaking after his death, Mr Howard's brother Jack said he had been "a lovely man, who would not hurt a fly".
"Bill was my brother and he was also my best friend," he said.
“We have been together for nearly 80 years and now I have lost him forever."