Senior citizen no other income,ltcg reinvested sec. 54, itr?

Dear Sir,

My mother inherited a share of residential property from her mother i.e. my grand-mother in year 1991 for Rs. 60,000 (60 thousand)  as her share, which she sold off year  June'2013 for Rs. sixteen-lakhs as her share.  Amount received is completely reinvested in our first residential house as joint property with me i.e. her son.

Other than this, she don’t have any other income.

I am confused, is she Liable to file any ITR for AY 2014-2015 for any such LTCG.

it will be kind of you, if you can let me know that Is it absolutely necessary to file NIL  ITR for this LTCG reinvested.

Thanks

Avishkar