What is the ruling of the Sharia on dealing with a father who is wasteful and negligent in his duties towards his family, and are the children obligated to support him financially?

The rights of parents are great, superseded only by the rights of Allah the Almighty. Allah has commanded kindness and dutifulness towards them, even if they are disbelievers. However, there is no obedience to them in disobedience to Allah. Obedience to parents is obligatory unless they command a sin. The financial support of a poor father is obligatory upon his children, as is the support for incapacitated siblings. There is no objection to living outside the parents' home, but this does not negate their right to dutifulness, kindness, and financial support if they are in need.