The victim was found at 8pm on Sunday 13 February 2022 near the bottom of a set of stairs in Victoria Street.
He had suffered a serious head injury and was taken to a local hospital where he currently remains in a life-threatening condition.
As part of enquiries, a man in his 60s from Chatham was arrested on suspicion of grievous bodily harm. He remains in custody at this time.
Investigating officer Detective Constable Beth Brimmicombe-Wood said: ‘Although we have arrested a man, we are working to establish the full circumstances surrounding the incident and are carrying out enquiries to ascertain how the man sustained his injuries.
‘We would like to hear from anyone who was in the area at the time who may have information about what happened and who has not yet spoken to officers.
Anyone with information about the incident should call Kent Police on 01634 792209 quoting 46/30477/22.
