Legal hierer

Hello sir, greetings of the day.
As per your query, if the head of the family dies without making a will i.e intestate then the property of the family head must devolve equally amongst all his legal heirs. Under Indian succession laws, both the sons have equal rights in his fathers and grandfathers property by birth. The sons will get equal rights over the ancestral property as does his father in his grandfather’s property. Besides in a situation where the father has a self- acquired property or any separate property and he dies intestate, then all his sons who come under Class I heir will have equal succession rights over his property. 
The two laws of inheritance in India that are applicable are:
The Hindu Succession Act, 1956/ 2005 - This Succession law applies on succession of property without a will i.e. intestate succession among Hindus and is also applicable to Sikhs, Jains and Buddhists.
The Indian Succession Act, 1925 - This Succession law is applicable on transfer of property of Hindus through any will i.e. a testamentary succession. 
So in this case you have to make both the sons legal heir and not only the older one, according to law. This is provided in both the laws of inheritance. 
Hope this answers your query.
Regards
Nirali Nayak
Law Student