Why is she so adamant on declawing??? What is her reasoning behind it other than her other cats having it done?

It's not your fault your sister is being a weenie... let's just hope that Gus will heal quickly and not decide to develop some bad litterbox habits after his declaw (if she wants to meet some that were declawed as adults that ended up with pain in their paws and bad litterbox habits, she can come over to meet a few of my fosters.... ). Honeybun still holds his paws up every couple minutes, and lord knows how long he's been declawed.

Poor Gus and kitten... we'll hope for the best for them.