Is it permissible to spend the profits from end-of-service benefits, which include usurious interest and stock dividends from usurious banks and financial institutions, to help a sister cover the expenses of an in vitro fertilization procedure?

If the bank deals with usury, it is not permissible to work there, due to the assistance it provides in usury. Similarly, it is not permissible to invest end-of-service savings in stocks and bonds that are not sharia-compliant and that receive usurious interest.

There is no harm in disposing of the unlawful returns from this work or from stocks and bonds by giving them to your sister for an IVF procedure, while observing the necessary sharia controls for the permissibility of that procedure.