i personally would just go ahead with the holiday (without thought for her) coz your kids deserve it! i'm sorry to sound harsh but her problems are not yours or your moms. at best imo all you can do is tell her she needs to grow up and get help! she's making your mom ill and stressing you ALL out and she needs a straight talk.

sorry if this is not what you wish to hear but it's just my opinion.

hoping for you and your kids the holiday goes ahead and is much fun .... and wishing respite for your mom