You can revive a total of 70% of losses (if lost in your own haven, 30% is for free). 70% of 2 is 0.70*2 = 1.4 which rounds down to 1 (because 1.4<1.5).

uminert said:

I was attacked on a treasure island and among other crew lost two War Elephants. Why is there only one in the Infirmary?

What level is your Infirmary?  

 Sorry, forget that

 if you lost units at treasure island then you can only restore 70% so Crow is correct