Re: My EX is not deserving of Mother's Day
My first child's dad was this way. However, I took the time to make sure my eldest (and all my kids) are aware of various mental health problems that adults can have. It stinks not to have a parent who will put the child above their own needs. However, that's life. You can teach them empathy while at the same time letting them know that you don't agree with the decisions their mother is making. My mother bailed on us when I was 10. She only claimed me after that when it was convenient...i.e. needing to look good for a boyfriend or a prospect. Usually it ended with the boyfriend feeling sorry for me and dating my mom long enough to give me some nice stability (i.e. weekends at their lakeside camp with my friends invited, help with getting a job, good meals, rides to school... anyhow, as a result of a parent being such a loser, I was able to experience the fact that the world is full of a lot of winners. Besides my mom's prospects, my friends parents and some teachers also pulled through for me, while allowing me to retain my dignity. And my dad, even though he had his own struggles, managed not to suicide until I was close to 18.
Parental abandonment stinks, but it's not the end of the world. Maybe your kids can send her a packet of seeds, with some kind of encouraging note about reaping what you sow (without meaning for it to be sarcastic, lol...) that is, she can choose to put down her roots wherever she likes, and have whatever she plants blossom. That way, they are still giving her flowers, but she has to grow them herself, and you're recognizing that ultimately, she will make the choice herself.
I also used to celebrate Mother's Day by honoring everyone who helped me to be a good parent to my children, either directly or as an example. You and your children could take the day to honor those people in your lives. You could help them make a bouquet of paper flowers that has a photo of each of their helpers/inspirations/sources of love and encouragement in the middle. It will help them to see that even though their mom is not with them, they have a lot of people who add up to a mom.
Alienating their bio mom might make it more difficult for her to make a choice to return. However, I understand, there is no need to reward her for her current choices. You could also send some pre-paid pre-addressed postcards with whatever card/gift is sent to her.
I got some flowers from my first child for Mother's Day already. I have no idea what he does if anything for his father on father's day, or his stepmother. he's old enough now so that it's his business. I certainly think about my mother around this time of year, and I feel sorry for her, however what she did to me was irrevocable. Later on she also called me possessed. I get it that she's mentally ill, but honestly, there are drugs you can take for that. She just doesn't want to face facts. Fantasy world...she lost her mom at age 10.
I wonder if there is something similar in your kids' mom's past that causes these problems for her? I hope it will resolve somehow and a better outcome for everyone involved.
Try not to burn bridges. At least so early on.