Is it permissible to prevent children from seeing their mother who was a disbeliever, then embraced Islam, then returned to Christianity, and this matter is pending proof?

Filial piety towards parents and maintaining kinship ties are obligatory, whether the parents are Muslim or non-Muslim, as evidenced by the Almighty's saying: "And accompany them in [this] world with appropriate kindness," and the hadith of Asma bint Abi Bakr. Therefore, it is not permissible to prevent children from maintaining ties with their mother and showing kindness to her, unless there is a fear of them being corrupted in their religion and morals, in which case they should not be entrusted to her. However, a mere visit from which no corruption is feared, it is not permissible to prevent it.