Here's my VP about him constantly texting you about the kids games/practices. I would tell him you have tried to keep him informed but he refuses to cooperate, go by a schedule, or meet with you to discuss things. Therefore, you are resigning as his personal secretary. Tell him not to expect any further assistance in "reminding" him that he needs to show up for his sons, and answering his redundant questions he texts. It is not your duty. He will have to get his information the same way you get yours.
Tell him that you want to have a set schedule so that both of you will know how to make plans for the boys and please do not text past bedtime wanting to have them the next day.
I would also tell him that he should stop texting you unless it is an emergency or of extreme importance regarding the boys.
Then you will have it in print as documentation.
And this business where he text at 10:00 at night asking you if the boys might want to do something with him the next day? Why on earth put up with it? If he won't cooperate with a schedule for the times he has the boys, then why should you feel obligated to soften his bed for him?
He is making you miserable. You can stop some of this stuff....if you want to. It's up to you.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!