Dear Mr. Gray,
Thank you for posting your request on History Hub!
We searched online and located the following statistics on World War II casualties. Many of these numbers were based on reports compiled shortly after the war, and most likely include those who died shortly after the formal end of the war of wounds received during the war, however most numbers are not broken down in that manner. The Army casualty statistics in the last report linked does include some charts breaking down casualties by month through December 1946 and includes persons killed in action or dying of wounds after September 1945.
We are unaware of comparable numbers for long-term casualties of those whose deaths many years after the war can be attributed in whole or in part to physical or mental conditions related to their service during the war. There have been some studies, such as The Life-Long Mortality Risks Of World War II Experiences, that may be of interest.
We hope this information is helpful. Best of luck with your research!