Urinary Retention leading to Acute Kidney Injury (AKI) or Sepsis: The patient's difficulty in passing urine and decreased urine output, especially in the morning, followed by altered sensorium, suggests a possible urinary retention that could lead to AKI or sepsis, particularly in the context of a recent fever.

Prostate Enlargement or Prostatitis: Given the patient's age and symptoms of urinary difficulty, an enlarged prostate or prostatitis could be contributing factors, potentially leading to urinary retention and subsequent complications.
Urinary Tract Infection (UTI): The recent history of fever and current urinary symptoms could indicate a UTI, which is common in older adults and can lead to more severe conditions like sepsis or AKI if not properly managed.
Dehydration: The patient's general weakness and decreased urine output might also suggest dehydration, which could be exacerbated by or contribute to the urinary difficulties and altered sensorium.

Sepsis: Although the fever has resolved, the potential for sepsis, especially originating from a urinary source, must be considered due to the patient's age and the severity of symptoms like altered sensorium.
Cerebral Vascular Accident (CVA) or Stroke: Altered sensorium could be a sign of a CVA, which is a medical emergency requiring immediate attention.
Spinal Cord Compression: This could explain both the urinary retention and altered sensorium, especially if there's a history of cancer or osteoporosis.

Neurogenic Bladder due to Diabetes or Other Neurological Conditions: Although less likely, conditions affecting the nerves controlling the bladder could lead to urinary retention and other symptoms.
Post-Renal Acute Kidney Injury due to Other Causes: Other obstructive causes like kidney stones or tumors could lead to post-renal AKI, presenting with similar symptoms.