Whether this property comes under Ancestor category or not.

A has purchased property in 85 & died in 88. He was unmarried and have mother,sis,bro in family. A’s mother also passed away in 2006. A’s one of the bro(B) has WILL in his favour written by his mother in year 2004 and he claims that as A was unmarried all his property rights were with the A’s mother under class I legal heirs so B has the entire rights. WILL is not shared and informed to be notarified. Query-1)As the property was not actually purchased by the mother whether she has right to write a WILL in her son’s favour B. 2)Whether this property comes under Ancestor category or not.