This information is incorrect. Widows were covered from the very beginning. Act 91 of 1891, which established the Confederate pension system, authorized pensions to "unremarried widows of officers, soldiers, sailors who died during the war."
Mothers of soldiers who "died single during or since the war" became eligible under Act 325 of 1905.
The primary purpose of Act 101 of 1915 was to redefine the indigency requirement. It set the value of real property (less homestead) at $500 and annual income at $250 as the threshold for determining indigency. Widows and mothers had been already covered by this time in 1891 and 1905, respectively.