Hi. I'm in the USA and training my own service dog. I did quite a LOT of research. And we have been through some things already. Maybe I can offer some help.
First off, according to the ADA, an ESA dog does NOT have the same rights as a Service Dog. So you can have an ESA dog and a Service Dog going into a building where dogs are not allowed, and the ESA dog would likely be asked to leave, where the Service Dog would be allowed to stay.
So what makes the difference? First, I would do an internet search for ADA Service dog laws. And do a separate search for which states allow service dogs in training to have the same rights as full service dogs. It varies from state to state.
Next, your dog would need training. His training would have to include at least one or more specific task exclusively to help you. For example, he could be trained to make sure you don't miss your pills, or trained to respond to high blood pressure so you have to take pills. They could also be trained to respond to physical assistance, like guide dogs, or getting things you drop. For PTSD they are even more things you can train them for, like I train mine to keep people behind me further away so they don't crowd, he gets stuff i drop, he reacts when i start getting stressed, grabs my can if i forget, and because he's not the best breed, he also helps by being a pain in the butt - i have to stay on my toes to keep him trained. I do want to train him as a therapy dog to help others too.
So your dog would have to be trained to help you medically or physically.
And he needs to be well mannered. If he barks, whines excessively, goes potty, etc, then it's not a real service dog and you'll be asked to remove him. If he pulls at the leash and is more concerned about other people instead of you, they can call you on that. So training is a big deal.
There are a lot of places to train him for you, but it's really not too hard to do it yourself. YOu do have to be consistent though. Every day, train something. There are some great videos out there. Make sure you pay attention to ONLY positive reinforcement techniques - hitting a dog will only make a bad dog worse.
I'm fading, so if I remember, I'll try to send you some links to get you started if you want.
And one more thing to remember. When learning a technique, you don't HAVE to use the control words or hand signals they tell you. For example, people put their hand down to have their dog give a paw. Me, I just point and say "left front" or "right front". So I use the same techniques, like treats at the right times, just my own words that are easier for ME to remember.
Hope that helps! Let me know if you want me to find a couple of good starter videos, and if you have a preference on what about.
Have a good evening.