What should I do regarding visits from relatives who are immodestly dressed, which causes me to waste time and miss congregational prayers, while my parents prevent me from advising them?

Visiting relatives is a religious requirement for maintaining kinship ties, provided one avoids falling into forbidden acts such as looking at non-mahrams or entering upon a woman who is alone. It is obligatory to wisely denounce anyone who exposes her 'awrah (intimate parts). Prayer must be performed in congregation, or the visit should be scheduled at a time that does not conflict with prayer. There is no obedience to a creature if it involves disobeying the Creator by preventing one from going to the mosque. One should be patient and persistent in acts of obedience, utilizing time beneficially through reading or constructive conversation, and enduring blame for going to the mosque. Lack of responsiveness does not preclude giving advice, and deviations do not prevent communication, but it is necessary to lower one's gaze and avoid sitting with women. If the visit necessitates falling into sin, then do not go, and maintain ties with them through other means. Be gentle with your father when offering an excuse.