I am married to a usc and my papers are being processed,my aunt recently asked him to file a I-864 for her to kids so that they can come to America sooner.My question is Can he do that? Is it legal? Please answer quickly.Thank you in advance

If your husband is making enough money to cover 125% of poverty line for you and any other person then he can do it. If he is not making enough money, then he can not do that. Even if he will file Affidavit of Support while making less money, the person will not get visa and surely will be asked to arrange for another Affidavit of support.
Good luck.

he does make enough to cover them but is it legal for him to do it?He isn't related to them and all of the documents we've seen so far says he has to be related?