As mentioned earlier the limits as far as Indian immigration is concerned are well covered in the answer to this question at Travel.SE (Travelling to India from China - Limit on Customs?),
Regarding phones specifically, legally, you can carry one personal phone and that's it. Any packaged electronics (the two iPhones your aunt plans to bring in) should be declared and if they are not declared, she risks being caught.
Another place where this is well covered is Can we carry three new smart phones in hand luggage to India?