Wholly depends on whether or not the court buys this as being defense of others– if we're talking realistically, there's not a lot of hope they wouldn't charge him with murder (since there's little evidence), so that'd likely be 5 to 10 years, and up to 20 years considering the fact the body was buried and then Kaede went into hiding. He probably would've stayed on the low end of that sentence tho.
In the manga however they both look pretty much the same as before, so he might've gotten like 1 to 3 years for hiding the body only, and miraculously gotten out of the murder charge... It's either that or he got the minimum for the murder charge-- 5 years doesn't change THAT much of a person's face so it's believable I guess.
I wonder how many years he spent in jail…