[quote=@Vilageidiotx]
<Snipped quote by Pepperm1nts>

What happened to Alexei? 
[/quote]

Probably gonna go with "died young". The life-expectancy for people with his condition was 11 years back then, and by the time he was killed IRL he was 13 so...

I figured that since the likelihood of him surviving is low, I need to come up with a way for a different male heir to have outlived him. Maybe Nicolas has another son, and that son is the czar that is killed.