Good luck, as another springer owner, I know how they bounce and turn fast. Re depression I have been on a crusade,on this forum, about the great results of B 12 on mine , for anxiety, depression, dry nose and lethargy amongst other things.
My sisters lab has had both legs cruciates done, separately. she tied him under the table, so he couldn't jump but didn't feel cut off from her . Time flew and he was soon better.
You had betters to stock up on six weeks of bones to chew, hope the surgery goes well.