Advice please - elderly cat not coping with new baby

[freshstart4us]

Would really appreciate some advice. Our cat is 15 1/2 and has been showing signs of deteriorating feline dementia for the last few years (loud random meows, disorientation, lack of interest in play, phases of poor grooming, unresponsiveness to name, noises, etc). She has always been very slim but she had also been losing weight, despite eating much more than she used to. Initially suspecting hyperthyroidism, several vet investigations including repeated urine and blood tests have not been able to identify the problem and age related deterioration was determined. She did have some adjustment problems when we had our first baby 3.5 years ago but we have just had our second 2 weeks ago and she has responded very badly. She has been staying outside in all weather, sitting on top of the flat roof on our extension, not even coming in to eat. We have been bringing her inside twice a day for food, which she has eaten sporadically, or feeding her on the roof when we couldn't reach her to bring her down; if we lock her in she just meows at top volume and is clearly distressed until we let her out again. She is very upset, and most worryingly her weight has plummeted and she is now skin and bone. I am afraid she is going to have a heart attack, and don't know whether it would be kinder to have her put down at this point, as she is no longer herself and not having any quality of life at all. We are also emigrating early next year and I had previously thought that she would not survive the required 90 day quarantine stay to come with us, so had decided to re-home her with my SiL at that time, but given the shape she is in also think that might be too stressful for her as that would be to a flat without outside access (she has been both an inside and outside cat at different stages in her life and I thought that might be good for her in her old age). Any thoughts or advice greatly appreciated.

[cozietoesie]

Is there the possibility of rehoming her with your SIL now? She might enjoy some greater peace and order if your SIL doesn't have young children?

[freshstart4us]

SiL is currently in the process of buying a place and isn't able to take her until that completes, possibly another month to 2 months away. But yes, if she lasts that long we will send her ASAP now.

[cozietoesie]

I think that that might be for the best. The household will probably be pretty 'approximate' for a fair while and she's clearly neither well nor happy at the moment. Indeed, if your SIL takes any length of time to complete, you might need to take earlier action I suspect. Has your cat been to the vet recently?