My oldest rat is approaching his end....

I'm currently embracing my first rat, and I think this is his last night.Over the last months he has slowed down and slept more, but was overall healthy and happy. A week ago he was his usual self, but within a very short period when next held him he had a lump twice the size of his head and his eyes had become grey and and hazy. He is 2 years 3 months and I new this day was coming, but I didn't think it would end like this . I wanted him to go peacefully in his sleep, but now I have to watch him suffer. My stepfather arranged for him to be pts Monday, so he would not suffer longer but I believe we were too late for that.
He no longer accepts the mushed food and water I have attempted to give him wth a syringe, I can feel him giving up in my arms. I raised him from a blind pup until now and it is torture watching my baby go like this. He is is gazing up at me with a look like he's saying "Momma don't be sad." and now he has curled up in the crook of my leg. I hold him now so I can comfort him until he passes on and I can't stop the tears, this is so hard I just needed someplace to place my emotions while I wait this out.