MIL losing her mind, how do I deal (DH in rehab)?

Background:

http://community.babycenter.com/post/a64287985/dh-in-rehab-called-his-parents-to-help-me?cpg=1


There's more background linked there too. But basically my DH is in rehab for a drug addiction. He's doing well. Up until this point I have dealt with her just fine. She tried to spill all her problems to my DH and he shut it down.


Current issue:

My DS is turning 3 this month! And my DH will be home for his birthday yay! He will not be home the weekend before so I planned his party for the weekend after. MIL and FIL are divorcing and selling the house. (This becomes semi relevant and is what she keeps trying to vent to my DH about). I sent her this nice invitation I made.


She replied with "You realize that is in the middle of my move day and I can't come, right? :-(" I said I didn't know but was actually planning it around DH being home. Sorry you can't make it. This is her response


"I know I've told you a few times...can probably find a text too.

I thought (DH) gets home (Monday before party) Or has it been extended? He hasn't talked to me since last Sunday...


I understand everything that's going on...I get it....

But I don't get that I'm rarely included, except when needed....

I know that you can't understand what I am going thru...but that's when families are supposed to be there.

Bad timing...everything happening at once...

But it is what it is and unfortunately my life is out of my control right now.


Good opportunity to have (FIL) there for (DS) birthday....


My apologies, there is no text about my move day. Guess it was just verbal. I know you have a lot going on your mind, can't expect you to remember anything happening in my life. Maybe I can come see (DS) another time next week.


All of you if course. But to bring (DS) a gift. And hugs for all .... "


These are paragraphs because she sent more than one text. I don't really understand her reaction but part of me wants to send her a therapist recommendation because omg fly off the handle over a kids party much? Normally I leave DH to deal with these things but...well he's in rehab and all. Also haven't taken her up on this help so that's an irrelevant line from her. I can't seem to form the words other than "fuck off"