I agree with Glow, the company in question should have a standard retirement policy.  Are you sure this isn't redundancy?  Might be an idea to know the age of the individual.  

I worked for a company a few years back who were letting go all of their over 50s and giving them a package.  Some were only 50 or 55, well below retirement age, so I would suggest this person finds out in writing exactly why they are being offered retirement and what the package entails.

25 years is a long time and it should be an ample retirement package the same as if it were redundancy.