Is it permissible to force a mother to write over a quarter of the house to her daughter, as she did with her siblings, knowing that the house is the family's sole inheritance, and the daughter is a widow with no one to support her?

If the house belongs to the mother and she gifted half of it to the two brothers, excluding the questioner, this is impermissible. Equality among children is obligatory. This equality can be achieved either by returning what was favored to some children or by completing the share of the others.

If the intention behind the writing was that the children would not own their shares until after the mother's death, then this is a will for an heir, which is impermissible unless all heirs agree to it.

However, if the house was inherited from the father and not exclusively owned by the mother, then the mother is not permitted to allocate an additional share to some heirs. The house or its value must be divided among all heirs according to their prescribed Islamic shares. In case of dispute, the judiciary will decide.

In all circumstances, children must honor and treat their mother kindly. It is not permissible to mistreat or sever ties with her.