Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
If most of your grandmother’s family members are Christians and they are refuse to allow her to be buried according to the Islamic rites, then you are absolved of sin.
Responding to your question, Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
If you have no control over their actions, you incur no sin. However, if you are her heir and legally responsible, you should take charge.
If that is not the case, and the rest of the family are Christians, and they are refusing to allow her to be buried according to the Islamic rites, then you are absolved of sin.
Allah says:
“Allah does not burden any soul beyond its capacity. To its credit is what it earns, and against it is what it commits. ‘Our Lord, do not condemn us if we forget or make a mistake. Our Lord, do not burden us as You have burdened those before us. Our Lord, do not burden us with more than we have the strength to bear; pardon us, forgive us, and have mercy on us. You are our Lord and Master, so help us against the disbelieving people.'” (Al-Baqarah 2: 286)
Having said this, I must rush to add: you should organize a Janazah (funeral) prayer for her in the mosque, even if you cannot bring her body. You should also visit her grave and offer prayers for her.
As our scholars said, “If you cannot do a thing (fulfilling all of its conditions), it does not mean you skip it altogether.”
I pray to Allah to forgive your grandmother, shower her with His mercies, and admit her to Jannah.
Almighty Allah knows best.
Source: AsktheScholar.com