Are paternal aunts considered next of kin (womb/ رحم) with whom it is obligatory to maintain ties, and is one sinful for severing them, and is it permissible to abandon maintaining ties with them on account of my father?

The paternal aunt is a relative by kinship whose ties must be maintained, and it is not permissible to sever them. However, if visiting leads to harm, then ties can be maintained through other means such as calling, gifting, and offering assistance. Problems that might arise from offering assistance can be avoided by providing it secretly. Responding to mistreatment with kindness greatly increases the reward.