Helloi Ms Preeti,
Your mother is having sleepless, fatiguibility & is loosing weight. The sleep disturbance appears to be secondary to some other problem.
She needs to be assessed in detail about her mood and thoughts, as
depression is very common at that age. Depression could be present without low mood but with fatigueness, decreased pleasure in activities with reduced seep and appetite.
I would be able to suggest you properly if you could describe-
any physical problems in your mother-like
high blood pressure,
diabetes, obesity or any other ailments.
Menstrual irregularities
Any behavioural changes- like crying spells, irritability, negative thoughts, worries, guilty conscious, decreased enjoyment
I would suggest you to meet a psychiatrist/
neurologist for proper diagnosis and treatment. As treating the cause is more important for a good relief than just treating sleep with sedatives which can become addictive and further disturbs sleep.