I am so frustrated with my MIL right now... Sorry, this will probably be long.

Yesterday she picked my 2 LO's up b/c daycare closed a half hour early. She tells me when I pick them up that she wants to take DS, 4, all day Wednesday, but that DD, 2 has to go to daycare. (She will pick her up at 5 b/c daycare closes early that day also).

I told her I didn't like to do that because DD gets upset. She's just not old enough to understand why DS gets to go and she doesn't; AND MIL took DS alone a couple weeks ago and promised to take DD for a full day and has not, so DD is getting the shaft.
I leave the convo. that its fine, DH will drop DS off at her house earlier, so hopefully DD doesn't get as upset.
Then this morning she texts me to tell DS, sorry she can't take him, because I laid all this guilt on her and she can't deal with the heartache. I suggested she just pick them both up early from daycare so neither is upset, and she says, "If I can put a happy face on".
UGH!!!

Not to mention that her other grandson, 3, is at her house all the time, and she picks him up 3x a week while my kids cry. They all go the same daycare, and we all live next to each other.

I'm trying to put both kids best interests in mind, and now I have to deal with her pity party on top of it.
How would you deal with her?