Dear Mr. Ben-Arie,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located List of United States Residents Serving in the British Expeditionary Forces, 1917 - 1919 in the Records of the Selective Service System (World War I) (Record Group 163) which includes a card for Jack Breslaurer. We are attaching a copy of the card.
This series has been digitized and made available online by our partner, Ancestry.com, for a fee, as U.S., Residents Serving in the British Expeditionary Forces, 1917-1919. Some libraries provide free access to Ancestry to their patrons.
The U.S. National Archives does not have service records of British military personnel. Please review the National Archives of the United Kingdom's research guide on How to look for records of British Army soldiers of the First World War.
We also searched online and located an entry for him at the Commonwealth War Graves Commission.
We hope this information is helpful. Best of luck with your research!