I have one sister that calls almost everyday to check in on mom and myself or stops by 4 times a week. GREAT. My other sister, who lives 15 minutes from us, is not working, is not ill, rarely calls, and might if we're lucky might come over once every couple of weeks. I had been very vigilante on calling this sister and giving her updates on mom, asking her to come over for meals, or just pop in. This sister states she wants to give me support, but it doesn't seem to happen.
It could be that she's on the defensive, is keeping her guard up so as not to get sucked into a situation she doesn't like the look of. But - not knowing her, of course - it could be just as likely that she's at a loss, doesn't know what support would look like in reality, and doesn't have any incentive to give it any thought.
So perhaps you could do worse than think of some specifics and ask her. Come for coffee on Saturday morning. Please bring groceries. Please come and sit with mother on Tuesday afternoon while I go to the dentist. Whatever.
I can't blame her for calling only rarely - if you're vigilant with the updates, what's she going to say?
There's no history between her and your mother, or her and you, or even her and the other sister that would make a difference, is there?
I am glad you have the support of your other sister. That will be a great help for this time in which you choose to be caregiver for your Mom. Wishing you the best of luck.
I am also one of 3 sisters, and mom lived with me; I was the primary caregiver. My oldest sister had (and has!!!) been stalwart in her support; she called me, called mom, faithfully came to visit every 2 weeks or so, even through the pandemic; along with my husband, she was my rock.
The middle sibling was a no-show. I would update; I got back radio silence. She never visited, never called me, rarely called mom. When there was an emergency - and let's face it, when you're talking about your 85 year old mother who is frail and has CHF, almost everything medical is an emergency - I would be asked "what can I do?" The only - *only* - thing I ever asked was for her to at least acknowledge my calls/texts and let me know she got them. She couldn't even manage to do that... she was always "sooooo busy at work!" No work that I know of will tell you to not even acknowledge a text message from your sister when your mom is dying.
When we got to the end - when mom was transitioning, my husband called her and told her, gently, if you want to say your goodbyes, you'd better come now. "I can't come tomorrow - I'm just sooooo busy with work, and they need me here, but I'll try to come Tuesday"... when she arrived with her idiot husband, he said to my husband "well I didn't think mom was that bad, I figured she's at least be awake and talking".
I'm not going to tell you not to be angry. That's just not reasonable. It's ok to be angry, as long as that anger doesn't permeate everything you do in your life, to the point that it starts to effect your other relationships. I wish I had some advice to give you, some magic words you can give your sister to "make" her care; but if this is who your sister is, there is nothing you can do to change it, and I'm so sorry.
Now that mom has passed, my feelings have changed. I realize I no longer have to be as concerned with absentee's sister's feelings being hurt because the closeness I have with my oldest sister leaves her "left out" so to speak - my concern was never really her feelings, but more that she would b**** to my mom about it, and put my mom in the bad position of being that mom with fighting children. I have to say, that it is a very freeing feeling! I actually think I have a little more patience now to deal with her than I did while my mom was still alive, if that makes any sense.
So my advice is to rely on the sibling you can rely on, and understand that the other sibling is the one who will be losing out at the end of the day. You have tried to include her in all aspects of what is going on with mom; it is not your fault - nor your responsibility- if she removes herself from the scenario and then has "buyer's regret" when all is said and done.
They may choose to step up, they may not.
My OS will do anything, if asked, but she doesn't go looking for 'trouble'. She's never helped out with anything related to upkeep of mom's place or running her to a drs appt. Because mom doesn't ASK.
My OS is wonderful and very kind, but emotionally, she's very flatlined. She doesn't have an empathetic bone in her body--but she will step up with the checkbook open if that is what needs to happen.
I tend to fuss and worry and end up getting my feelings hurt, where she never gets in a situation where that can happen.
Also--my standards are not hers. So what I look at as a huge problem to solve, she'll sit back and wait for it to work itself out. I'm beginning to learn that 90% of my 'worries' are pointless and a waste of time.