Question: What was the army rank of Mildred Gale's grandson?

Context paragraphs:
Lieutenant (Canada): Lieutenant is a rank of the Canadian Army and Royal Canadian Air Force.  The equivalent rank in the Royal Canadian Navy is sub-lieutenant.  A naval lieutenant is one rank superior to the army rank of lieutenant and the naval rank of sub-lieutenant.

Lieutenant (British Army and Royal Marines): Lieutenant (Lt) ( ) is a junior officer rank in the British Army and Royal Marines.  It ranks above second lieutenant and below captain and has a NATO ranking code of OF-1 and it is the senior subaltern rank.  Unlike some armed forces which use first lieutenant, the British rank is simply lieutenant, with no ordinal attached.  The rank is equivalent to that of a flying officer in the Royal Air Force (RAF).  Although formerly considered senior to a Royal Navy (RN) sub-lieutenant, the British Army and Royal Navy ranks of lieutenant and sub-lieutenant are now considered to be of equivalent status.  The Army rank of lieutenant has always been junior to the Navy's rank of lieutenant.

Veebel: Veebel is an Estonian military rank which has existed since the 20th century.  The word "veebel" is derived from the German rank name of Feldwebel, and is usually, but incorrectly, translated into English as Sergeant.  The official translation given by the Estonian Army is Warrant Officer, although the rank is equivalent to the British Army rank of Sergeant in the NATO code.

List of Field Marshals (Australia): Field marshal is the highest rank of the Australian Army and was created as a direct equivalent of the British military rank of field marshal.  It is a five-star rank, equivalent to the ranks in the other armed services of admiral of the fleet in the Royal Australian Navy, and marshal in the Royal Australian Air Force.  The subordinate army rank is general.

Risaldar-major: Risaldar-major was originally a cavalry officer of the British Indian Army, the rank was created in 1886 - a risaldar-major was the most senior risaldar (army rank equivalent to a captain) of the regiment.  The rank was a Viceroy's commissioned officer in the cavalry.

Mildred Gale: Mildred Gale (1671–1701), born Mildred Warner in the Colony of Virginia, was the paternal grandmother of George Washington, the first president of the United States.

Captain (armed forces): The army rank of captain (from the French "capitaine") is a commissioned officer rank historically corresponding to the command of a company of soldiers.  The rank is also used by some air forces and marine forces.  Today, a captain is typically either the commander or second-in-command of a company or artillery battery (or United States Army cavalry troop or Commonwealth squadron).  In the Chinese People's Liberation Army, a captain may also command a company, or be the second-in-command of a battalion.

Amaro Soares Bittencourt: Amaro Soares Bittencourt (1885-1963) was a diplomat, a military and civil engineer and a general officer of the Brazilian Army, who attained the Brazilian Army rank of General of Division or in its original Portuguese "General de Divisão" (the equivalent U.S. Army rank is Major General).  During the Second World War, then Brazilian “General de Brigada” (Brigadier General) Bittencourt was the chief of the Brazilian military mission to the United States, that is the military attaché at the Brazilian Embassy in Washington, D.C. Bittencourt was also a member of the Brazilian delegation to the Inter-American Defense Board.  In October 1942, he became the first recipient of the United States Legion of Merit (Commander).  France awarded Bittencourt the Legion of Honor (Officer) for his wartime service, and Brazil awarded him the Order of Military Merit (Brazil) or in its original Portuguese the “Ordem do Mérito Militar”.  The Major General was a graduate of Brazil’s Escola Militar and its Escola de Estado-Maior.

George Washington: George Washington (February 22, 1732 [O.S. February 11, 1731]  – December 14 , 1799) was an American politician and soldier who served as the first President of the United States from 1789 to 1797 and was one of the Founding Fathers of the United States.  He served as Commander-in-Chief of the Continental Army during the American Revolutionary War, and later presided over the 1787 convention that drafted the United States Constitution.  He is popularly considered the driving force behind the nation's establishment and came to be known as the "father of the country," both during his lifetime and to this day.

Lieutenant field marshal: Lieutenant field marshal, also frequently historically field marshal lieutenant (German: "Feldmarschall-Leutnant" , formerly "Feldmarschallleutnant", historically also "Feldmarschall-Lieutenant" and, in official Imperial and Royal Austrian army documents from 1867 always "Feldmarschalleutnant", abbreviated "FML"), was a senior army rank in certain European armies of the 17th to 20th centuries.  It emerged as the rank of field marshal (German: "Feldmarschall" ) came to be used for the highest army commander in the 17th century (having originally been the equivalent of a cavalry colonel).  In German-speaking countries the commander-in-chief usually appointed an "under marshal" ("Untermarschall") or "lieutenant field marshal" to support and represent the field marshal.  Amongst his functions as the personal deputy to the field marshal, were the supervision of supply depots and routes, and inspection of the guards.

Supporting paragraphs: Mildred Gale George Washington
Answer: Commander-in-Chief