All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
In regard to gifting the reward of good deeds to a dead Muslim, then the most preponderant opinion of the scholars is that it is permissible and the dead benefits from it; for more benefit, please refer to Fatwa 83855.
We mentioned “a dead Muslim” because it is not permissible to gift good deeds for a non-Muslim and he does not benefit from it in principle. Moreover, a non-Muslim is not called a believer because he disbelieves in Allaah, Allaah Says (what means): {And whoever desires other than Islam as religion – never will it be accepted from him, and he, in the Hereafter, will be among the losers.}[Quran 3:85]
For more benefit, please refer to Fataawa 91537 and 90698.
As regards helping that woman to be moved to a place where she can be buried instead of being cremated, then this is a good thing, because in Islamic Law, a dead person should be buried and not cremated because cremation is strictly prohibited; Allaah Says (what means): {Then He causes him to die, then assigns to him a grave.}[Quran 80:21]; for more benefit, please refer to Fatwa 84963.
Finally, we advise you to do your best so that those people embrace Islam and you should clarify to them that Islam is the true religion, especially by having a good behavior with them, and if a person is sick or (physically) weak (because of being advanced in age), then it is most likely that he/she would accept the truth.
In this regard you may make use of some Fataawa about an introduction to Islam and the true God; you may refer for example to Fataawa 88906, 81529, 84349 and 89122.
Allaah Knows best.