What is the meaning of adding "and upon the heir is the like of that" in the verse "And mothers shall suckle their children for two whole years, for him who desires to complete the suckling"? And why is the heir mentioned here and not in the verses of inheritance? And is suckling for two years a recommendation or an obligation, and is there sin if the period is shortened or extended?

There is no basis for questioning the absence of this phrase in the verse of inheritance, for the discourse here is not about clarifying the inheritance of heirs. Rather, it is about clarifying who is responsible for the mother's expenses while she is breastfeeding the child. Completing two years is not obligatory; rather, the duration may be shortened by agreement and consultation between the parents, as Allah the Almighty says: "But if they both desire weaning by mutual consent and consultation, there is no blame upon them."