Do the two apartments built by the sons with their own effort and the approval of their deceased father enter into the total inheritance to be divided among the heirs?

What your brothers built could be one of two things:

1. They built it as a gift to the father or the family, in which case it becomes part of the father's inheritance and is divided among all heirs.

2. They intended to keep it for themselves, in which case it is their property and does not become part of the father's inheritance. However, fairness must be observed among children in giving gifts. If granting the right to build to your brothers, to the exclusion of the others, was based on a reason that necessitated their preference or with the consent of the other children, then there is no problem. But if it was an impermissible preference and the other brothers did not agree to it, then justice must be observed in dividing this right, either by giving the remaining children an opportunity to build, or by having the owners of the two apartments pay a financial compensation estimated by experts. The most important advice is to be keen on harmony, love, and maintaining kinship ties.