Wally's jawline mass needs surgery

I've had Wally the Shichon since he was 9 weeks old.  He is now 8 years old.  Seemingly out of nowhere, at the end of February of this year, I was rubbing Wally along his jawline and felt a lump on his right side.  Afraid to apply much pressure on it, I just lightly felt along it and found it to be about the size of a walnut. Wally had more of a shaggy haircut at the time so I just didn't notice anything different about him.  I took him to the vet and now here we are in March and he has gone thru waiting and waiting and numerous phone calls at the vet office.  I even had to switch vets because I felt he wasn't being taken care of in a timely basis.  It has since increased in size. I got him a 2nd opinion last week and then the consult with the emergency veterinary clinic today and he has a MANDIBULAR SALIVARY MUCOCELE MASS.  They are telling me they want to remove all his salivary glands on his right side.  The cost for his surgery is thousands more than my vet had estimated.  I don't know how I can not give him more of healthy life and go ahead with the surgery even though the cost is very much out of my price range.  I asked what would happen if he doesn't get the surgery and they said it would always need to be watched over to make sure not getting bigger or infected. He is supposed to have surgery in one week.  His diagnostics today were $645.00 And surgery can be upwards of $4295.00 they are telling me.  They also mentioned too the possibility of overlooked cancer that I pray it won't be..Please, if anyone is willing to help it would be so appreciated.  Wally is a huge part of my life, full of life and such a fun little guy. UPDATE: Wally has his surgery April 7 in the AM. I will let you know how he does.