I would have to go with the druid not being harmed, and this is even supported by the rules.
If the rogue jumped into a lake, would a pocket prevent the pocketed druid from getting wet? If not, then he isn't in Total Cover from a Spread Effect.
If the Rogue jumped into the lake he wouldn't be trying to evade the water. That is similar in supposing that the Rogue jumped into the fireball blast, not trying to avoid it. The Rogue evaded the fire, which means his clothing and items evaded the fire. For the fire to have burned the druid, means the Rogue's clothing (and pocket, specifically), would have to have been damaged. They weren't, as defined by a successful reflex saving throw.
As for the argument about creature/object. The druid's body in the pocket is still an object, only the fact that he/she is alive makes it a creature, but the body is still an object and one that is carried inside a container (object) on the Rogue's person. If the druid was dead, the body would not have had to make a saving throw against the fire. Why should it have to just because it had a heartbeat? It was still contained (complete cover) by the pocket. Now if the Rogue were carrying a full-sized druid in his arms, of course, both would have to make a save and that is likely what the rules meant when interpreting the difference between an object and a creature.
If you want to talk about rules, then consider page 152 of the 3.5 PHB where it talks about varying degrees of cover. Peering around a corner or through an arrow slit, as examples given in the book, results in the person getting Improved Evasion. Complete cover (inside the pocket of a Rogue that Evaded a fireball) should qualify as such improved cover and then some!
And on page 176, an otherwise solid barrier (which a closed pocket of a successfully Evasive Rogue would be) needs a hole in it 1 square foot or larger otherwise the barrier blocks the spell's line of effect. I don't think the pocket opening on that Rogue was 1 square foot or larger. So, no line of effect to the druid, no saving throw required.
Evasion is NOT a feat that is shared.
Evasion is not even a feat. And it is "shared" when considering all of the Rogue's belongings. If the Rogue is not damaged, then none of his belongings would be. Contents of containers aren't damaged until the container is destroyed, and since the pocket took no damage from the fireball, you couldn't justify the contents taking damage. Even then, take note of that Improved Evasion point above for superior cover. Even failing the save, the druid still should have taken only half damage--which would mean no mass damage save and a still living druid. Maybe if its not too late, the druid could "wake up" and resume travelling with the group.
In fact, when the Rogue Evades, he most likely put some of his equipment between himself and the blast (a common sense explantion for avoiding damage completely), hence, some of his equipment should be a penalty to the save.
Says who? That is just your assumption/explanation. Ask anyone else you know and they'll all give you varying descriptions of Evasion, and I doubt any of them will involve throwing the character's gear between them and the danger. The specific definition is using "great agility" to avoid certain spells and effects. I didn't see "put as much of your gear between you and the danger and hope for the best" in that description.
Like I said, if its not too late, maybe the druid can wake up after only suffering half damage even if the DM insists on requiring a save despite common sense, physics and (most importantly

) the rules stating that it is not. Maybe the druid was just frightened of the thought of being roasted alive in the Rogue's pocket and fainted 'dead' away.