Are children sinful for not accompanying their elderly father to the mosque on Friday, given difficulties such as slow movement, the possibility of involuntary urination, and difficulty sitting? And what is the optimal solution in this situation?

One is not permitted to miss Friday prayers and congregational prayers except for a legitimate Shar'i (Islamic legal) excuse. Allah the Almighty has commanded striving to remember Allah on Friday, and the Prophet, peace and blessings be upon him, warned against abandoning Friday prayers and intended to burn the houses of those who failed to attend congregational prayers. Therefore, attending Friday prayers and congregational prayers is important for anyone who does not have an excuse, and weakness and old age do not prevent this as long as the person is able to go to the mosque. Hence, one should help their father attend the congregation of Muslims, unless doing so would cause harm, while emphasizing filial piety and obedience to parents, especially in old age.