Good as a true dragon though
If you are referring to my cursed coin dragons, they could grow quickly on Midgard relative to the Faerie Realm, but they would grow and age very slowly relative to Midgard if they were in the Faerie Realm. Now, that could be useful to some extremely long-term plots on the dragon's part, as he wouldn't need to sit and twiddle his claws, and could zip through the wait time, but it would otherwise age the dragon just the same.
He would also have the Con and HP's to outlast thirst and starvation.
Interestingly, according to the Rules Compendium, a
Heal spell can cure someone of dehydration and thirst (but doesn't heal lost HP's when doing so), but cannot heal someone of starvation.
...[given water and under care for 24 or 48 hours with a Heal check, blah, blah]...Once a Heal check of this sort has succeeded, the damage taken by the creature can be restored through the normal means.
A heal spell can be used to rehydrate a creature in place of the recovery time, water, and a Heal check.