Per la parte fisica sono d'accordo...ma riguardo le caratteristiche mentali secondo me si incrementano, per i motivi di cui sopra...chiederò al master, a meno di non trovare l'argomento specifico scritto su qualche manuale...

io master li concederei i bonus mentali se gli alleghi un buon BG

i non morti subiscono vantaggi e svantaggi derivati dalla vecchiaia?

Al riguardo esiste questa FAQ:

Does a human who becomes an undead apply the ability score adjustments as he ages?

The Sage recommends that aging effects not be applied to a PC who becomes undead. It seems unreasonable that an undead’s physical ability scores should change based on the original race’s lifespan (why should a dwarf vampire stay strong longer than a half-orc vampire?). Similarly, applying adjustments to mental ability scores seems to create more problems than it’s worth. Should a skeleton that’s been dead for 200 years be wiser than one that was just created? If a long-dead ghost gets smarter with age, why doesn’t a long-dead mummy? That said, if a DM wanted to apply aging effects to ability scores for undead PCs, it’s not terribly unbalancing. He should just be prepared to answer a lot of corner-case questions—and most DMs will find it more hassle than it’s worth.