My Uncle an US Citizen, is passing his old age in India and is resident as per Indian tax laws. He receives Social Security pension in form US Government, which is credited to his US Bank account and then as and when required, he seeks remittance to his Indian bank account. He also receives, Interest from bank on his Fix deposit or credit balance. He owns some shares in US.
I would be thankful to know:
1.Whether Social security pension credited in US bank account is taxable in India,
2. Whether amount remitted to Indian Bank account taxable in India ? Would it make difference if, amount now remitted is out of his savings from income earned in past?
3. Whether interest credited to US bank account taxable in India, even if not remitted to India?
3. Any Double taxation benefit available?

1.Whether Social security pension credited in US bank account is taxable in India?

India has a comprehensive Double Tax Avoidance Agreement with USA. As per Article 20, Point 2 of the said DTAA, social security pension received by a resident of India from USA is not to be taxed in India.
Therefore, amount credited into US bank account is not taxable in India.

2.2. Whether amount remitted to Indian Bank account taxable in India ? Would it make difference if, amount now remitted is out of his savings from income earned in past?

No. ( same explanation as in question 1 holds good for this as well)