Can the father take some of his daughter's Mahar money and use it for his wedding party? Can the father take some of his kid's income if needed?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

It is unlawful for the guardian of the woman to take anything from her dowry unless her guardian is her father and he had stipulated this for him as a condition in the marriage contract, in which case, it becomes permissible for him to take what he had conditioned according to the predominant opinion of the Scholars .

Besides, it is unlawful for the woman's guardian to take a portion of her dowry without forcing her and provided she gives that to him with her consent and out of her own free will. The Prophet said: “The money [property] of a Muslim is not lawful for anyone except with his own consent and will.” [Ahmad and Al-Bayhaqi]

If the father is needy or poor, then his expenses should be paid by any of his sons or daughters who are wealthy; each according to his wealth.

They should also help him get married to keep him chaste or just to help him have someone who serves him provided that he does not have someone to do so or that he has a wife but she does not serve him because of being too old, or too young, or sick.

However, if the father is wealthy or the children are poor, then it is not an obligation on them to do any of the mentioned matters except if they do it as an act of piety or as a way of keeping ties with him.

Allah knows best