I am not usually overwhelmed either, but I have to tell you and not sure if you have ever been a caregiver. I don't care how laid back you think you are, you caregive long enough and things can change in an instant from what was a easy situation to a more difficult one and you will get burnt out if you don't take care of yourself.
The whole resentment/it's not fair argument always kills me. Life is not fair. Everything is not always equitable, even between siblings. You sound like you have your hands full, and like you don't want to do this. I don't blame you a bit, a person can only take so much. If your daughter has a problem with it, guess what, it's HER problem. If she wants to stew and be resentful about it, it's her choice to feel that way. She could also choose to think "you know, mom does have a lot on her plate, I hadn't really thought about that." As a Mother, sometimes our first instinct is to put our children first, but sometimes you need to put yourself first, and once your children are adults, you should put yourself first most of the time.
It is easy to say the DD should grow up and know things aren't fair, than why shouldn't the other sister? She could put her child in after school care or before school care. She is living for free so she should be able to pay for that.
Also it is also easy to sit here and say the OP should just say no but is she ready to not have a relationship with the DD? or to not see her new grandchild? If the DD gets mad and hurt or her husband.
I think both girls need to look at what the Mom has going on and both deal with it. If the one DD is getting free rent then maybe she could watch the baby if it is at times she is around. Or put her son in after school care so the mom is available. Or stay with the grandparents so her mom could go to the other girls house for the baby.
I firmly believe with kids it doesn't have to be 100% equal but it should be fair and giving one DD everything and the other nothing isn't either.
First of all - I'm so sorry you are so stressed about this!
I am amazed at all of my friends - and friends here on the DIS who feel that their parents owe them childcare! Taking care of my own children was at times a handful - so I can't even imagine being older and having to take care of my parents and grandchildren.
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Just want to let all of you know how much I valued everyone's input.There are times when you need the opinions of those who are detached from the situation to help you to see things more clearly. My parents are a big factor in this equation; at their age, I have to be prepared for anything to happen. I am their only child, and of course I want to be there for them. My new little grandson, is equally important to me, but I know that I cannot pull this off on my own. As many of you have suggested, both daughters, and my DH will need to step up to the plate to make this work. I plan on having a family meeting tomorrow; I'll let you all know how I made out. Wish me luck.

There's an idea. Could you share the care of the elderly parents and the 2 children amongst the 3 of you? For example, you look after your dgs before and after school, youngest dd looks after the infant on Saturdays or a night or two when older dd has to work, and older dd takes her grandparents to Dr's appointments?
Man, I'd already be stressed with that many people living in my home. We bought our home to fit our family; it's not very big, so having all those people, and juggling laundry schedules, making room in the kitchen for different food needs/preferences, and taking care of getting them to appointments, etc would be a lot for me. If the OP's parents have moved in with her, she may well be helping them with lots of "daily life" activities already.

Don't overextend yourself. If you really feel like you can't take on any more then don't. It ticks me off when kids expect their parents to care for the grandkids or expect everything to be equal between siblings.
My brother couldn't wait for my mom to retire so that he could get free childcare. My brother and his wife struggle month to month and my mom is one of those guilty moms who says yes to anything when it comes to us kids. Because she watches my brother's kids so much I don't often ask her to watch my kids because I know that there are things she wants to do now that she is retired.
I'm not resentful that she helps them out more, but I am resentful that my mom worked so hard for so many years and now she feels obligated to help them. She loves her grandkids dearly but I know she wants to travel and do lots of other things that will be difficult to do because of the commitment she made to babysit. She would feel very guilty going back on that commitment for any reason.
ETA: My brother is completely capable of getting a part-time job in the evenings and on the weekends. He just doesn't want to.
I totally agree with this. My family is the same way. I have an aunt and uncle that took care of their grandkids for years and wanted to travel and do other things. Now that the grandkids are old enough to take care of themselves, my aunt and uncle are not well enough to travel or do the things they wanted to do. I'm not saying they never traveled, but not to the extent they wanted to.
What I don't understand is why kids these days (20 to 30 somethings) feel that they can do this? Grandparents love to see their grandchildren and watch them on occasion but not full tiime - its draining!!! Grandparents are not in their 20's and 30's anymore.
I understand completely on treating their children equally and not doing for one and not the other. I wonder how these parents will be when they have grandchildren - will they watch them full time for their kids or will they say, sorry we have other plans.
