Surgery for my dog, my best friend.

I am a retired military veteran with PTSD. I am going through a divorce and relocation which has significantly affected my savings account. Max is my best friend and is a family member to my kids. Recently Max has been struggling to get around and has had a clicking in his knee that has progressively gotten worse. He's in obvious pain and discomfort. After his visit at the vet today I was informed his ACL is tore and the surgery to repair his leg is $3500. I do not have the means to cover this surgery and it will be devistationg to put him to sleep. Any help will be appreciated. Thank you from me and Max.