Marrying an athiest

Assalaamulaikum respected mufti, my mothers sister married an athiest over 30 years ago, in that time he did not convert nor did she practice her religion. last year she was diagnosed with lung cancer and then she started reading her namaaz and quraan again. She is still married to the man, and neither he nor her children have excepted islam. She is dying now as her cancer has spread and her sisters have rallied around her praying for her. I would like to know if she is still in the fold of islam and whether we can make dua for her. Allah knows best. Jazaakallah