Dog ate rat poison with Bromethalin in it

Hello vets, Our dog got into some rat poison this morning around 11:15 am, after my dad got ahold of me, I got dressed, and Blaze loaded up, we drove 90 miles to the emergency vet and arrived around 2:00 pm. The rat poisoning did have bromethalin in it so they had him throw up 3 times which was 90% green each time. They attempted to continue to get him to throw up but he would not so we aren’t sure if it would have still been green or started to clear up. They gave him a hefty amount of activated charcoal and sent me home with enough for 7 doses of 60ml and a timeline to follow when to give it. They reccomended a very bland diet of only white rice for today and tomorrow we can add some chicken. We were also told that if we don’t see symptoms before Monday then that would be a very good sign but also that most dogs who get ahold of the poison with brometholin in it don’t stand a very good chance. Also that once he starts showing signs that something is wrong that there’s basically nothing that could be done and we should think about euthanasia. My questions are, - how soon/ late could we see symptoms? He’s acted completely normal no signs of acting lethargic, off balance, siezures, etc - is it looking promising that we haven’t seen any symptoms out of him yet? - if you had to give me a percentage what percent chance would you say he can survive? - is there anything that you would recommend or could tell me to help our boy out? He’s been with our family since I was 12 and he was 6 months and we love him very much. We didn’t know there was even rat poisoning in the very back of the pantry and are heartbroken over the thought of losing him Pics of our sweet boy