What is the ruling on a father refraining from attending Friday prayer in the mosque due to a dispute with a neighbor, and how can he be advised to pray, and does sin accrue to the son for not speaking with him about this matter?

You must disapprove of your father's absence from Friday prayer and advise him, because this wrong might not be known to anyone else, otherwise you would be sinful. Missing Friday prayer is only permissible if the harm inflicted upon him by his creditors is imprisonment or constant harassment. However, merely encountering a neighbor does not waive its obligation. Remind him of the Hadith: "Do not hate each other, do not envy each other, do not turn away from each other, and be, O worshipers of Allah, brothers. It is not lawful for a Muslim to forsake his brother for more than three [days]." If he insists, he can pray in another mosque.