In terms of what might be useful for you, as one who accepts the Buddha's teaching is...Sn 3.8: Salla Suttahttp://www.accesstoinsight.org/tipitaka ... .irel.html
... however, your mother may not share this world-view and as such, may not find consolation in it. In fact, it might anger her.
Whatever you do, best to regard her with compassion and endeavour to help her through her grief, using the Buddha's teachings to support yourself
(and thus making you of more use to her as a support).
"Do not force others, including children, by any means whatsoever, to adopt your views, whether by authority, threat, money, propaganda, or even education." - Ven. Thich Nhat Hanh
"The uprooting of identity is seen by the noble ones as pleasurable; but this contradicts what the whole world sees." (Snp 3.12)
“One to whom it might occur, ‘I’m a woman’ or ‘I’m a man’. Or ‘I’m anything at all’— Is fit for Mara to address.” (SN 5.2)