i'm also not a friend of many back-in-time series, they tend to introduce randomly established characters or events we've never heard about before and want us to simply accept it as a matter of fact.
"Oh, I finally meet my best friend again, eventhough I never referred to him in the first 15 chapters."
or
"Of course this is going to happen and I knew it all along. Back then it was a tragedy and massacer. Many died, it was a horrible blow for the Alliance and many refugees starved to death to following winter, but I didn't care preparing for the event or warned anyone about it. I AM HERE to handle it. Oh boy, I surly hope nothing unexpected happens and the event derails, because my knewledge about its backgrounds might be incomplete. Well, here I come to save the day!"
If the whole spiel is about changing the future for a better and you already changed stuff in the very beginning, and you brought amazing future tech and/or magical knowledge with back with you, don't go "Better not change too much, so I don't lose my advantage of knowing the future." If you already changed it, it already changed. Well, it's just beginning and I also hope it goes into a different route, but.... he could have given that amazing adoptive father of his a warning, who in turn could have given the evacuation order and take up a tactical better position for the upcoming fight. I don't think, he would have doubted him that much, to not at least take some precautions. Just saying.