MUSLIM SONS' INHERITANCE SHARE
Muslim Sons under Islami law inherit as a Joint Residuary with Daughters otherwise, they inherit residue as an independent. Sons get double the share of Daughters under Joint Residuary as stated in the Holy Quran, 4:11. Sons do not inherit fixed or prescribed division share.
The Father cannot disinherit children in Islam and must follow Faraid as stipulated in the Holy Quran, 4:11.
There is certain Hajb (i.e. blocking or exclusion) rules are applicable for descendants. Sons block Sons of Sons (how low soever) and also block siblings and their descendants. Sons also exclude Granddaughters (how low soever).
Sons inherit from their parents (i.e. Husband or Wife) only if their parents were married Islamically (i.e., Nikah) otherwise, they are not eligible under Islamic law. In the same token, if they married Islamically but do not have registered marriage or other evidence of marriage, then spouse and/or children cannot inherit legally.
An estate from a Muslim son can be inherited by his wife, children (or grandchildren), and parents (or grandparents) as primary heirs. These are the legal heirs after the death of a married son in Islam. Refer to "Islamic inheritance sharers and residuary" to learn more.
Sons also can own lifetime gifts (i.e., Hiba) from their parents without any classification or restrictions, but all children should be treated equally for lifetime gifts as stated in the Book of Hadith, Bulugh al-Maram, Book 7, Hadith 928; "My father went then to the Prophet (Sallallahu Alayhi Wasallam) to call him as a witness to my Sadaqah (i.e., gift), and he asked, "Have you done the same with all your children?" He replied, "No." He said, "Fear Allah and treat your children equally." My father then returned and took back that gift." If you want to give more to one child (or children) than the rest child (or children), please consult a knowledgeable Sunni Islamic scholar.
Wassiyyah's Islamic inheritance course can give you more insight in learning this topic. We encourage you to read our book, which includes exclusive details about Islamic inheritance sharers, shares, residuary, and distant kindred relatives.