Undiagnosed adult daughter

Hi, I’m new here, and hoping for insight and advice. My daughter, 39, hasn’t been diagnosed with autism, but we strongly suspect that she has it. She has had very strict rules governing all aspects of her life, in particular food, but really lots of things. She also has obsessions that she will talk about, in great detail to anyone who takes the time to listen. She has always struggled to form lasting friendships and relationships. Despite all of this she has had a good life. She has worked in retail for 20 years, mainly because the thought of looking for something else has filled her with dread. She has managed a small China and glassware store for the past ten years. Last September she was diagnosed with stage 3 cervical cancer. Two weeks after that the company announced that they were closing her shop. This would all have been a lot for most people, but for her it has been a nightmare. We live close by, so have been there for every step, but the treatment has left her a wreck. The personal nature of the cancer has meant that her dignity has been diminished, and on top of that she was admitted to hospital for nearly a month due to excessive pain. We knew that this would be hard for her, but we didn’t realise how hard. She barely ate. The food was not prepared in the right way, it wasn’t what she was used to, it arrived at the wrong time. The staff were concerned about it, but didn’t know what to do with her. Anyway, we finally got her out, and she was desperate to go back to her own home. We know her well enough not to argue, but were concerned that she wouldn’t cope, so we decided that we’d go round a couple of times a day. She didn’t last 24 hours before she wanted to come to ours. Hooray, we thought. We can get her strength back, and let her go when she’s ready. That was two weeks ago. The first week was fine. She ate rice cakes and melon mostly, and although she was understandably emotional, she felt like she was getting stronger. She has now rediscovered her food preferences, and we’re at our wits end. We don’t know how to make it easier for her, or frankly, for us. She hasn’t eaten now since Christmas day. We nearly got her to eat this morning, she wanted a bacon roll, so my husband went out to buy bacon and rolls, and then I gave her the wrong ketchup. I’m sorry I’ve rambled on so much. I think what I’m hoping for is other people’s coping strategies and advice. We’ve tried asking her what she wants, suggesting that she sits in the kitchen with us and supervises the cooking (we have food she likes, but we don’t cook it the same way as she does), we’ve suggested that she comes shopping with us, or that we go and see what’s in her freezer, nothing seems to appeal. She can see for herself that her behaviour is different to most people. She said to me yesterday that she had a headache, felt sick, and was very hungry, but that she couldn’t think of anything she wanted, so nothing was better than something. She described herself as insane. I told her emphatically that she was not. I’m concerned. Normally I wouldn’t be. I would think that once she was home she would sort herself out, but she’s trapped at ours, recovering from chemo, radiation, and brachytherapy, and she’s barely eating. I know she’ll refuse any medication or intervention by a professional. I just want my beautiful, perfect, lovely girl to be happy and well. Help.