R Yaakov Goldstein in his book The Laws & Customs of Mourning Vol. 2 writes (here online)
An Avel [who is the son of the deceased, whether the deceased is his
father or mother], is to lead the prayers as Chazan for every
weekday prayer, if he knows how to do so. [This applies even if
there are other potential Chazanim available. He is to push ...