Possible Clues:

• Suffering from ailments of old age
• Suffering infirmities of old age
• Area of England, by the river, that has decayed
• Declining, in a way
• To the south-east of the old river
• South-east of Old Man River?
• So old as to be able to see just about nothing of the river at last
• Showing the failings of old age
• Getting too old to look about nothing at all, and is wandering
• South-east of the old river