Should one leave a family group on WhatsApp where objectionable things are posted, such as celebrations of the Prophet's birthday (Mawlid) and accompanying forbidden acts like music and pictures of women, despite attempts to denounce them and the members' unresponsiveness? And is this group considered an assembly of vice that must be abandoned, given that leaving it does not mean severing family ties?

If the violations in the group are not prevalent but rather incidental, then it is better for you to stay to clarify these violations, mitigate evil, and disseminate purposeful and influential content, while choosing indirect methods and considering their psychological readiness. Furthermore, your presence enables you to show kindness to them and endear yourself to their hearts, for "kindness is the key to hearts." The group is not a gathering of disobedience if its original purpose was communication. So, if you find a violating post, overlook it and communicate with the poster privately. However, if evil acts become frequent, and they do not respond to your advice, and you fear for yourself, then it is safer to leave the group while maintaining communication.