Deduction under Section 80D for senior parents of senior citizen

Sir,

I do not have any policy and my wife is also not covered under any policy.

I am a senior citizen and my wife is 55yrs.

1)What deduction can I claim under section 80D.

2) What documents I have to provide or keep with me?

My mother 79 yrs old is covered by my brother office policy. however her medicines are not covered.

I spend regularly on her medicine. Can I claim deductions for the Same.Do I need to keep medical bills of each month with me.