Friend Shields
Here's an idea I'm throwing out there after seeing a friend's city get demolished cuz she couldn't get back online for a few days... Friend Shields.
It could be either a special item or just an added capability to activate a shield for your friend. There are ways to limit it if there is concern that this would be abused. You could have a 12 hour limit and only be able to add a shield to someone whose shield has already dropped. Since they've likely already been burned before a clan mate actually notices and reacts this would at least give them a chance to begin recovering resources and stop people from farming them down to nothing before they can come back online. I've seen in some games where a short shield is automatic after a person has been attacked. This would be something similar but would depend entirely on the help of the unlucky person's clan mates and still gives the small bit of hope that they'll be seen unshielded and rescued before an attack. It's just hard to sit by and watch a friend get burned when there's nothing you can do. ._. lol