Is it obligatory for a mother to be just among her children in giving, and does the ruling on her giving differ from that of a father's giving?

There is no blame on a mother for singling out one of her needy children for a gift, to the exclusion of others. She is not required to equalize among them in this situation, because the singling out is justified. Ibn Qudamah explicitly stated the permissibility of singling out one of the children for a reason, such as their need, chronic illness, or preoccupation with knowledge, and he narrated from Imam Ahmad what supports this. Likewise, Ibn Uthaymeen said that if one of the children needed to get married and he married him off, he is not obligated to give the others the same. There is no difference in this ruling between a mother's gift and a father's gift; both are equal concerning the obligation of justice among children, unless there is a justification.