Resources / advice for extreme anxiety of other dogs?
My pup is now 11 months old (male, not neutered) and has always been a bit hesitant towards dogs and people. But from around 6 months old he started being reactive on walks. Where he used to ignore or rather avoid other dogs, he now lunges towards them from a mile away, barking until the trigger is as good as out of sight (and even then he keeps on looking behind).
He also started jumping at everyone we pass, although not barking or growling but when someone wants to give him attention, he backs away out of fear. In spite of this, when we have visitors at the house, he is a bit uncomfortable at first, but when we ask our visitors to ignore the dog, his curiosity quickly wins it from his fear and he starts approaching and even asking for some pets.
Now my sister has a pup (9 weeks, female) and brought her for a first visit today. We decided to have a baby gate in between the dogs so they could each choose to approach or to back away with enough room to do so. My sister carried her pup inside and my dog was first very excited (he has a crush on my sister we believe) and tried to sniff her pup. But once she was freely moving on the ground behind the gate, my dog got extremely anxious. Intense barking, nervous tail wagging, hyperventilating, panting, very warm paws. He was unable to calm down in any way. So we did the only thing that calms him down and tethered him out of sight of the other pup. After some time he finally stopped barking and started showing interest in the high value chew we had given him and in the end he went to lay down.
But every time my sister's pup got some attention or made some noise, he was panting and whining again. I have been reading up on canine sensory processing sensitivity and am pretty sure he has it. However my current book feels so out of touch with reality saying that you need to accept your dog as he is and consider moving to the countryside and all or rehome if you can't provide his needs. Obviously this is not realistic and there should be a way to help my dog deal with this anxiety. So I am wondering if anyone has experience with this and can help me find some better resources, online training courses, what worked for them,... I don't need them to be best friends, but I would just like to help my dog with this anxiety because it breaks my heart to see him like this and it is impossible to avoid all dogs for the rest of his life.