Actually as concepts go I think it is excellent. Red Alert was based on the premise that Hitler was eliminated before he rose to power and, without the German war machine to grind down the Russians they rolled over everything (which is certainly a plausable alternative history).
Many senior figures in the British government wanted to appease Hitler. Churchill was pretty much a lone (if loud) voice and we probably would not have gone to war when we did if not for him. He also played a major part in keeping us going and in getting the Americans to join the war when they did. If the UK had not entered the war Germany would not have needed to waste troops & resources on the Atlantic wall and as a result might well have beaten Russia. Had we entered the war without Churchill we might not have got the covert support we did from the US and we would have been defeated/surrendered.
It’s a well documented fact that US infantry soldiers and armour were pitiful when compared to their German counterparts and often failed to win encounters despite a more than 2:1 advantage. With Russia and Europe defeated (and Japan as an ally) Germany would have been able to stage an invasion of the US and would almost certainly have won.
The early death of Churchill wouldn’t have stopped the UK or US from entering the war but it would almost certainly have delayed both events and that would have allowed Hitler to focus his efforts rather than splitting them.