What a Decrepit Old Tosspot !
Without American efforts in the European theatre in WW2 we would have lost, but the Russians actually won WW2 in Europe.
So YES the old fart is correct, but there is no need to brag about it.
An American saying is that "the British will fight ton the last American".
https://www.msn.com/en-gb/news/world/donald-trump-insults-britain-s-brave-war-heroes-by-claiming-america-won-the-world-wars/ar-AA1E4Jqe?ocid=msedgntp&pc=U531&cvid=e057bc262480483283565b5a72b15133&ei=19