Prince Leopold, Duke of Brabant
Prince Leopold of Belgium, Duke of Brabant, Count of Hainaut (12 June 1859 – 22 January 1869), was the second child and only son of King Leopold II of Belgium and his wife, Marie Henriette of Austria, and heir apparent to the Belgian throne.
Henry IV, Duke of Brabant
Henry IV of Brabant( 1251/1252 – after 29 April 1272) was Duke of Brabant from 1261 to 1267.
Born at Leuven, he was the eldest son of Henry III, Duke of Brabant, and Adelaide of Burgundy.
Succeeding his father at about the age of ten, he proved infirm of mind and body, and was deposed in favor of his younger brother John I, Duke of Brabant.
After being deposed, Henry became a novice in Saint Bénigne Abbey in Dijon.
It is unknown what happened to Henry after 1272.
Matilda of Brabant, Countess of Artois
Matilda of Brabant( 14 June 1224 – 29 September 1288) was the eldest daughter of Henry II, Duke of Brabant and his first wife Marie of Hohenstaufen.
Margaret of Flanders, Duchess of Brabant
Margaret of Flanders( died 3 July 1285) was a Duchess consort of Brabant.
She was the daughter of Guy of Dampierre and his first wife Matilda of Béthune.
She married John I, Duke of Brabant in 1273.
She was the mother of:
John IV, Duke of Brabant
John IV, Duke of Brabant( 11 June 1403 – 17 April 1427) was the son of Antoine of Burgundy, Duke of Brabant, Lothier and Limburg and his first wife Jeanne of Saint- Pol.
He was the second Brabantian ruler from the House of Valois.
John III, Duke of Brabant
John III( 1300 – 5 December 1355) was Duke of Brabant, Lothier, and Limburg( 1312 – 1355).
He was the son of John II, Duke of Brabant, and Margaret of England.
Prince Leopold, Duke of Albany
Prince Leopold, Duke of Albany,( Leopold George Duncan Albert; 7 April 185328 March 1884) was the eighth child and youngest son of Queen Victoria and Prince Albert.
Leopold was later created Duke of Albany, Earl of Clarence, and Baron Arklow.
He had haemophilia, which led to his death at the age of 30.
Marie of Évreux
Marie d' Évreux
( 1303 – October 31, 1335) was the eldest child of Louis d' Évreux and his wife Margaret of Artois.
She was a member of the House of Capet.
She was Duchess of Brabant by her marriage to John III, Duke of Brabant.
Her paternal grandmother being Marie of Brabant, she was a great- granddaughter of Henry III, Duke of Brabant and so, her husband's second cousin.
Marie was the eldest of five children born to her parents.
Marie's younger siblings included: Charles d' Évreux; Lord of Étampes, Philip III of Navarre; husband of Joan II of Navarre, and Jeanne d' Évreux; Queen of France by her marriage to Charles IV of France.
Maria of Brabant, Duchess of Bavaria
Maria of Brabant( 1226–1256) was a daughter of Henry II, Duke of Brabant, and Maria of Swabia.
She married Louis II, Duke of Bavaria, being the first of three wives.
Marie Henriette of Austria
Marie Henriette of Austria (Marie Henriette Anne; 23 August 1836 – 19 September 1902) was Queen of the Belgians as the wife of King Leopold II.
Marie Henriette was one of five children from the marriage of Archduke Joseph, Palatine of Hungary, and Duchess Maria Dorothea of Württemberg.
Marie Henriette was a cousin of Emperor Ferdinand I of Austria, and granddaughter of Leopold II, Holy Roman Emperor, through her father.

Question: Who is Prince Leopold, Duke Of Brabant's maternal grandfather?
Answer: Archduke Joseph, Palatine of Hungary