The washtowel pays lip service to this. They tell people that it is a moral obligation. Usually, what happens is that it falls by the wayside when field circus and boasting sessions come due. I had one witless in my former congregation that did this--putting an aged mother up in their house, and then to a nursing home. (This family always went by the letter of what the Filthful and Disgraceful Slavebugger said).
As to whether it is proper or not, that depends. I do not believe in honoring parents that are mean spirited, always sabotaging the children's attempts to succeed and grow. To honor one's parents should be a volitional decision on the part of children, and the parents should do what's reasonably possible to earn it. Generally, children whose parents have supported their efforts to the best of their reasonable abilities instead of sabotaging them will help support the parents in times of need, while those whose parents always undercut their efforts will not.