Javasnake

I have a boa that is almost 25 years old and I have a few questions for any one who may have experiance in this area.
1- How old can a red tail boa live (yes, I know, at least 25 yrs)
2- she's declined significantly over the last few years (loss of appeptite, weight loss) is there anything I can do?
3- has any one ever tried "loading" food items with added nutrients and how did you do it?

Thanks, I appreciate any information you might have.