Is it permissible for me to ask my husband to obligate his brothers and sisters to share in bearing the costs of their sick mother's treatment, knowing that sending all of our savings will affect our future and our housing?

It is permissible for the questioner to speak to her husband so that he may ask his brothers and sisters to contribute to the costs of their mother's surgery, if they are well-off. This is a form of righteousness (birr) and may become obligatory for them if the father is unable to cover the expenses, as the preponderant opinion is that the husband is responsible for his wife's medical costs. The contribution should be according to the financial capacity of each individual. However, if they are in financial hardship, it is not appropriate to ask them, as this would cause them embarrassment and burden them with what is not obligatory.