Hi Sabbirnbd, thanks for your question.
As a duldung holders , your child will also get the same status which you or your wife having because none of you is holding German resident permit. In case, one of you as the parents or two of you is holding German resident Permit then your child will be qualify for resident permit under the Para. ยง33 of German law but because you and your wife are duldung holders, the child will also get the same duldung and I'm sorry to hear that on your side, it shall be well for you and your family.