I have to agree with some who think that your friend fibed about the vet's comment.

Like others here, we also foster and adopt out cats. We used to foster dogs too.

It doesn't sound like the friend was ready for a forever companion. And it was a right decision to return instead of keeping the dog. The dog would have become more of a burden than a family member. Really sad to see the dog panicking but I hope his next adoption will be the right one, to a forever family.

If you think about it, there are no perfect forever pets. Just like children, they will get into trouble from time to time. From glass half-empty perspective, all pets have issues. For those of us who are commited to our animals, we see their faults/issues and accept them along with what they bring into our lives. We learn to live with their issues just as the animals do with our issues.

friend sent me this the other day.

A Lesson in Humility
If you can start the day without caffeine,
If you can get going without pep pills,
If you can always be cheerful, ignoring aches and pains,
If you can resist complaining and boring people with your troubles,
If you can eat the same food every day and be grateful for it,
If you can understand when your loved ones are too busy to give you any time,
If you can overlook it when those you love take it out on you, when, through no fault of yours, something goes wrong,
If you can ignore a friend's limited education and never correct him,
If you can resist treating a rich friend better than a poor friend,
If you can face the world without lies and deceit,
If you can conquer tension without medical help,
If you can relax without liquor,
If you can say honestly that deep in your heart you have no prejudice against creed, color or politics,
Then, my friend, you are almost as good as your dog.

-Anonymous
Your friend isn't ready to have a dog in the house. If she wants to have a dog again, suggest her to foster a dog and see for a while. If her interest in the dog wanes, the dog will be adopted out. The only drawback is, are there any resuce group willing to take her on as a foster parent.

I hope the dog will find a forever home. very sad.