Does refraining from speaking to one's father for long periods constitute a sin if the father does not pray, does not honor his own parents, does not care for his children, and does not respect his wife?

Abandoning one's father is not merely close to sins; rather, it is forbidden and among the grave major sins, as it constitutes disobedience to parents, which is considered a major sin. Many شرعي (Islamic legal) texts have been revealed, urging kindness and good treatment towards parents, including the Almighty's saying: "And your Lord has decreed that you shall not worship except Him, and to parents, good treatment" (the verses). The questioner must hasten to reconcile with his father and seek his رضا (pleasure), and fulfill his rights outwardly through connection, inquiry, and financial support if necessary. His father's disobedience and shortcomings do not justify abandoning him; rather, he must accompany him with kindness and advise him gently and leniently, and depart from him when he commits a sin without assisting him in it.