OP:
I don't think your (former) Mom Boss is really going to put her child into a daycare & that is why she is letting you go.
No way!!
It appears to me that she is doing a bait + switch move on you.
She listed in the contract that you have access to five sick days, but didn't think you would truly need them.
That's like telling your cancer friend you will clean her house for free, then when she asks you, you mutter a "Oh.... I didn't think you would actually ask me to!"
WTF??!
Yep, same logic here.
She knows fully that she is in the wrong here & is protecting herself.
She told you the reasoning for your dismissal yet wrote another reason in the letter since it gives her a legit reason to let you go.
Just in case you choose to sue her.
She is just a common flake.
I don't know if this situation would have a chance for success in a court of law.
I wouldn't fork over any dough for an attorney however. Your best bet would be a small claims court for sure.
If possible, try visiting a free Legal Aid Centre in your city (if you have one) for some advice about if anything can be done legally over this.
Your Mom Boss sure made damn sure she covered all her tracks on this.
Good luck to you and I hope you eventually prevail!
You most definitely have been wronged here!!