MN is such a weird place. You get all these threads where posters claim to be crying over a complete stranger’s story and are falling over themselves to offer financial help, free stuff and other kinds of support (even though many of those threads absolutely scream fake or scam). But when it comes to doing anything at all for their own mother or - OMG, the horror - their MIL, it’s a very different story. For some reason, threads about elderly parents / PILs asking for even just very basic support or semi-regular phone calls often attract a pretty unpleasant crowd. Lots of people who seem to detest their mothers (who were of course all narcissists) and would apparently prefer to never see or hear from them again. It’s quite depressing, really.
OP, I’m really sorry you’re feeling rough and lonely. During the last 1.5 years, my own mum went through six months of chemo (also breast cancer) and a (fairly complicated) wisdom tooth extraction, so your story feels close to home.
During the cancer treatment, I drove mum to all her chemo sessions (weekly during the last three months), accompanied her to most doctor's appointments (I’m not in the UK - we were able to do this despite Covid), researched all her treatments and how to ease side-effects, prepared lots of nice meals and treats, did a fair amount of gardening, cleaning, dog-walking and life admin, made sure she always had fresh flowers and nice movies to watch and called her at least once a day. Took care of my step-dad when mum had her OP, went to see her in hospital every day, picked her up from the dental surgeon when she had her wisdon teeth out. We’re very close and I was utterly devastated when mum got her diagnosis. Not doing everything I could to support her seemed unthinkable to me, so I really feel for you.
Mum says several of her friends commented that their own children had been much less supportive in similar situations and how lucky she was. One of these friends does a ridiculous amount of childcare to support her daughter’s career, involving a 3 hour round trip several times a week. From what I can tell she is genuinely lovely, very warm and incredibly supportive of both her children, but apparently neither of them particularly cared when she went through years of extremely grueling cancer treatment. I’m not convinced the fault always lies with the parent or that there must be some sort of huge backstory. Some people just seem to lack empathy somewhat and are quite selfish by nature. It also seems to be cultural shift in Western societies. The way we treat our sick and elderly as a society is shameful and at a family level, in many cases things don't look much better either.
Only you know if there’s more to the story with your daughter, but if you’re generally close, I completely understand why you feel unloved and disappointed. If your daughter’s recent lack of care is out of character for her, do pick up the phone, find out if there’s anything difficult going on in her life, try to make some nice plans together and have a proper talk at some point. I hope things improve for you, you’ve been through a pretty tough time and anyone would feel a bit fragile after that.