All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is an obligation upon the husband to be just between his wives in relation to spending the night with them and providing them with food and clothing.
Allaah says (what means): {And if you fear that you shall not be able to deal justly with the orphan girls, then marry (other) women of your choice, two or three, or four but if you fear that you shall not be able to deal justly (with them), then only one.} [Quran 4:3]
However, there is no harm -Allaah willing -if one wife enunciates some of her rights. So the conduct of your husband should be according to the above, as in principle, we should think good of him and consider that his conduct is free from dishonour.
However, if it becomes clear that he is unjust to her, then you can advise him in a good manner, by choosing the appropriate time when he is relaxed as, in this case, it is expected that he would take heed.
As regards the child benefits, it is the right of the children. If there is no particular condition by the department offering these benefits, then they have more right in deserving it. But if the husband is in need to spend on himself or whomever he is obliged to spend on, then he can take from this money according to what is reasonable without being extravagant. It is confirmed that the Prophet said: "You and your wealth belong to your father." [Abu Daawood and others]
Finally, it should be noted that this husband should fear Allaah and endeavour to earn his daily bread; Allaah says (what means): {He it is, Who has made the earth subservient to you (i.e. easy for you to walk, to live and to do agriculture on it, etc.), so walk in the path thereof and eat of His provision, and to Him will be the Resurrection.} [Quran 67:15]
Al-Bukhari and Muslim reported that the Prophet said: "The upper hand is better than the lower hand."(The upper hand is the hand that provides and the lower hand is the hand that begs).
Allaah Knows best.