Peace be upon you and God's mercy and blessings.
Grand Ayatollah Sayyid Khamenei (may God protect him):
It is not permissible to give Zakat to those whose maintenance is obligatory upon the person obligated to pay it. Therefore, it is not valid to give it to parents, grandparents, children, grandchildren, or a permanent spouse. However, it is permissible to give it to siblings and their children if they are poor.
Yes, if there are obligations of maintenance towards these individuals that are not related to their personal expenses (like payments to a wife), it is permissible to give them Zakat under that title.
Grand Ayatollah Sayyid Sistani (may God protect him):
It is not permissible to give it to those whose maintenance is obligatory upon you, such as a father or son. However, it is permissible to give it to them if they have needs that are not obligatory, such as if the father has a wife whose maintenance is obligatory upon him, or if he has a debt that must be paid, or if he has work that requires payment and is dependent on money. As for giving him extra for comfort beyond what is necessary, it is more cautious to avoid this if he has means to provide for them.
May you be successful in all good.