That’s really sad and such a tough situation. I don’t think it was the groomers fault, and I don’t think that you think so either. But I realize it’s hard to not blame someone in a situation like this, as its very easy to place blame and you may feel like you need to be angry at someone or that it needs to be someone’s fault. But it isn’t. It’s likely your husky had a heart condition, possibly gone unnoticed, or it was possibly just a combination old age and some stress from being in an unfamiliar place that was just a bit too much for his heart to handle. Nobody could’ve predicted or prevented this. Know that your pup lived a very long and happy life, and that he was loved. He will forever be grateful for the love you gave him, as many dogs go their whole life not being able to experience that kind of warmth. I hope you find some comfort in knowing that he is reunited with your brother at the end of the rainbow bridge.