The Calendar of Council Minutes 1668-1783 (Google Books) lists for December 1749:
“Order in regard to Indian children, taken in pawn by Mr Bradt and Peter van Driesen of Schenectady. Negroesin Albany grown very insolent since the peace.”

The Calendar of Council Minutes 1668-1783 (Google Books) lists for July 10, 1751 (p. 381) “Speech of Massachusetts commissioners read. Order in regard to the Indian boy in possession of Johannes Bradt. The Indian boy turned over to the sheriff; Johs. Bradt to be prosecuted by information. Col. Johnson given charge of the Indian boy to return him to his parents. Royal mandamus appointing Col. Wm Johnson of the council’; he is sworn in and takes his seat.”

The Colonial Laws of New York from the Year 1664 to the Revolution (Google Books, Commissioners of Statutory Revision, 1894) lists Chapter 1063, An Act for Payment of the Debts of this Colony, passed June 3, 1758, including the following paragraph: “Unto Captain Johannes Bradt for himself and Company of Militia on several Marches on the Frontiers aforesaid against the enemy from the Tenth of September One thousand seven hundred and Fifty five to the twenty Seventh of February One thousand Seven hundred and Fifty Eight by order of the said Colonel as per account the sum of three hundred and Twenty five Pounds and Thirteen Shillings.”