I have a american daughter, my son 7 yold in Brazil will be ilegible to come to usa with tourist visa and her birthday?

Under the current regional ban for Brazilians, you and your son should be eligible to enter the US after satisfying any COVID protocols of the two countries. The regional ban has an exception for spouses and children of permanent residents. The proper visa for your son would appear to be O-2 dependent since you intend for him to spend some time with you. You should contact the US Embassy or Consulate to determine the schedule of whether and how soon he can obtain a visa interview. If not possible because of Covid, you should prepare to explain the situation to an immigration inspector if he comes with you under the B-2 visa. Due to the limitations of the Lawyers.com Forums, Alan Lee & Arthur Lee, Esqs.’ (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.