I haven’t heard specifically of dogs trained for this, but it’s absolutely possible in my opinion. Dogs can sense things we can’t, especially in the humans that they love. It’s pretty amazing!
I have a 7 year old Rottweiler, who is a trained service dog. He can smell a seizure before I am about to have one and pats me on the leg until I take my medication. We began training him when he was 6 months old. My Rottweiler before him could do the same thing. Unfortunately, he passed away at the young age of 2 years old from bone cancer. (which we were informed was a direct result from inbreeding)
I hope that this helped to answer your question. I do believe certain breeds of dogs are better at being service dogs than others.
Yes they can sense these things. My dog was acting weird and trying to alert me about something going on with my husband. I didn’t think much of it at the time, but moments after Surf came to get me, my husband, who is an otherwise healthy man in his 30’s, suffered a TIA.