I don't really know why its getting such high ratings, the actual story devices are super weak.
He has to leave the country after killing everyone in that gang that would even know who he was? why? and he can't take them with him because "he doesn't know what he'd face" ... like google is a thing, there is about 100 perfectly safe countries to travel to.
Sell their house, move to Australia [or Philippines, Indonesia, Puerto Rico, Costa Rica .etc He could actually sell the house and buy a boat that they could all live on while they travel to their new life.] live a safe and happy life. Job done.
I just think the plot detracts from the rest of the work that was done by looking like it had very little thought put in to actually make it believable.
IE: It failed to suspend my disbelief.
Here is a perfect quote to illustrate what I mean;
MC says "No one can hurt my family again." "who ever comes, who ever it is, I'll kill them. I'll kill them all."
No you wont, you'll be in a different country for two decades, dickhead.
Literally anything could happen and the MC will be in no position to do anything about it.
In fact by being absent he'll be the one doing the most damage.