Is it obligatory for children to support their father's wife, or is it a matter of exceeding generosity? And is what appeared on the brother of strange occurrences under the influence of ruqyah considered evidence to accuse the father's wife of magic and sorcery?

A stepmother should be treated with kindness, in compliance with Allah’s command and out of filial piety towards the father. As for her maintenance, it follows the father’s maintenance: if he is poor, his maintenance and his wife’s maintenance become obligatory. It is not permissible to accuse a Muslim of dealing with sorcerers without legitimate Shar’i evidence. It is advisable to maintain regular recitation of adhkar (remembrances) and du’as (supplications). If keeping a distance from her resolves problems and reduces animosity, then that is preferable.