Our shih tzu needs surgery!

Please help save Buckeye! My sister is a single mom with two amazing sons.  She is a 6th grade teacher who is already having hard times making ends meet.  Her son leaves for college in the fall and she is already stressing about how she will help pay for that. Then she finds out that her dog, Buckeye, is in need of surgery.  She has cried for days and is devestated that she simply doesn't have the funds to cover it.  Buckeye was getting groomed when the groomer noticed that it looked like he had blood in his urine.  My sister took him to the vet and unfortunately he has a bladder stone that is the size of an egg!  Some stones can be dissolved with a special diet, but this is not the case with his.  The only way to fix the problem is surgery.  I can't begin to explain the relationship my sister has with her dog.  It's her best friend and companion and I can't imagine her life without him.  He is only 5 years old -- too young!  Anything you could help with would be greatly appreciated.  Would be so nice to lift this financial burden for her.  She simply has no money for this surgery.  Thanks in advance for your help and concern!