Since they are US residents (Green Card) they are required to report their worldwide Income.  If they receive income from the accounts in India they have to report that income.

Thank you , So they need to declare even if they never used or brought that money into USA ?

If so , does this mean for last few years they are will be considered as no complaint with requirements ?

What type of income is being produced from those Indian accounts?  Interest, dividends, sales of investments which would produce a capital gains, retirement account income?

Mostly Fixed deposit (Like CD in USA) which will give interest after maturity. All the income in those accounts are earned in India when parents use to work and paid India tax as per requirements. 

If they are not being claimed as dependents and their gross income from all sources was less than $24,400, assuming that they would file jointly, they would not need to file a tax return.