Final answer:
A 65-year-old male with aching and sensations in the legs that disturb sleep is likely experiencing Restless Leg Syndrome (RLS), often treated with clonazepam, melatonin, and sleeping environment modifications.
Step-by-step explanation:
The most likely diagnosis for a 65-year-old male experiencing unpleasant aching, drawing, creeping, and crawling sensations in the calves and thighs with an irresistible urge to move the legs is Restless Leg Syndrome (RLS). This condition is associated with difficulty falling or staying asleep due to an uncomfortable urge to move the legs. Restless Leg Syndrome can be associated with neurodegenerative diseases like Parkinson's disease. Treatment options may include clonazepam or melatonin to help manage the symptoms and improve sleep quality. Environment modification is also a part of treatment to ensure safety and comfort during sleep.