This is what the Revenue say:
Who is a first time buyer?
A first time buyer is a person, (or, where there is more than one buyer, each of such persons):
who has not on any previous occasion, either individually or jointly, purchased or built on his/her own behalf a house (in Ireland or abroad) and
where the property purchased is occupied by the purchaser, or a person on his behalf, as his/her only or principal place of residence and
where no rent, other than rent under the rent-a-room-scheme, is derived from the property for five years after the date of the current purchase.
Seems to me: That she may well be a FTB for the purposes of stamp duty; therefore is the property is bought in her name it might qualify, provided its the principal residence. If its an investment property, dont think that will work.