Thank you for your question. May Allah reward you for asking this important question, and I pray the care of your mother will become easier on all of you and bless you all immeasurably for taking care of her.
Who Is Responsible?
The support of a widowed woman falls on her sons, equally, as her primary financial supporters even if one is wealthier than the other. As for the daughters, they must support their parents if they are able to and if their brothers are unable to support the mother. Please see the details here:
Goodness To Parents
The reward and rank of a person who takes care of his parents are tremendous and should be seen as such. The Righteous Caliph, ‘Ali ibn Abi Talib said, “Goodness towards (one’s) parents is the greatest obligatory act.”
And Allah, Most High, tells us, “Your Lord has commanded that you worship none but Him and that you be kind to your parents. If one or both of them reach old age with you, do not say to them a word of disrespect, or scold them, but say a generous word to them. And act humbly to them in mercy, and say, ‘My Lord, have mercy on them since they cared for me when I was small.’” [Quran, 17:23-24]
The rank of the mother is even higher than the father’s as we know that Paradise lies at her feet. I pray that you and your siblings can share in the blessings of caring for your mother and partake in the reward that will follow, by the grace of Allah. Please remember that Allah will send you someone one day to treat you in the same way that you treated your mother, so please love for her what you love for yourself, may you be blessed! Please see these link as well:
[Ustadha] Shazia Ahmad
Ustadha Shazia Ahmad lived in Damascus, Syria for two years where she studied aqidah, fiqh, tajweed, tafseer, and Arabic. She then attended the University of Texas at Austin, where she completed her Master’s in Arabic. Afterward, she moved to Amman, Jordan where she studied fiqh, Arabic, and other sciences. She recently moved back to Mississauga, Canada, where she lives with her family.