What is the ruling of Islamic law regarding a father who bequeaths all his possessions to his children from a second wife, thereby disinheriting his children from the first wife without cause, and is it permissible to boycott him and not visit him while he is bedridden?

Scholars differ concerning the ruling on a father gifting some of his children to the exclusion of others without a legitimate reason, and the preponderant opinion is that it is impermissible. It is not permissible to boycott him or refrain from visiting him, especially since he is ill and in need of service and care. His error does not justify disobeying him or treating him poorly.