This is such a worry for everyone, my mum has also been in a CH since January , had a lot of infections and lost weight. Her memory is now almost non-existent and she refers back to her teenage years all the time, asking me how her "our" mum and dad are (I think I fluctuate between being her sister or her daughter, depending on the conversation and who I am with at the time). My father (long deceased) is now never mentioned and we've learned the hard way which subjects are anxiety provoking ,which are the safe ones. We've stopped trying to have a "meaningful" conversation with her, and she's happy to just have me or her grandchildren sit with her for an hour or so,or we take her out for a drive and a meal and try to keep everything happy, smiley and up beat. At times I still miss being able to have a moan to her about my job , my man or my children (as you do) and hearing her stick up for me while at the same time telling me I told you so, etc. (rose tinted hindsight will get you every time - so much loss to deal with - I still can't face packing up her home and belongings - I pick up a photo frame or look through her cupboards and it sets me off again - honestly, I could carry home spuds in the bags under my eyes.
But the weight loss is a worry - I think if she doesn;t like the food at meal times they don't always offer her anything else and she wouldn't think to ask because, to her, nothing else is available, if it's not within her range of vision or hearing then it doesn't exist. The staff don't always seem to understand that PWD often need a visual or verbal prompt, something we as a family learned the hard way. Staff will make her something if I ask, but I can't be there every mealtime and all I see is my mother getting thinner and more frail each week. But on the other hand they are very good at giving her the reassurance she needs, and they take good care of her through the night when she agitated or anxious and wants to wander around. I am slowly learning to accept what will be will be and that I cannot control everything that happens to her.