Filing of it returns for ay 2017-18 & 2016-17 for house wife

Hi! Friends,

My Mother In law is a House Wife aged 68 Yrs and getting Interest on Fixed Deposits (Rs.2.0Lacs) on her savings

Recently, we undeerstood the bank, TDS was deducted from her Interest payments due to non submission of Form-H/G for Senior Citizens (She is having PAN Card).

Can we file her Income tax Return for previous 2 or 3 years to claim refund of Tax and if we do so will it attract any penalty for late filing of return. Her Total income may be @ 1.00Lac/Year

Pls. clarify