Is there a range of factitious disorder severity?

I am wondering if there is a range of factitious disorder severity. My sister was diagnosed with epilepsy aged 3. I witnessed many seizures back then, in our childhood. There was an unusual family dynamic with my parents giving into most things especially if it had to do with her seizures (ie particular drinks she said she needed to swallow pills, getting my mother on her side for any little argument with me, indulging her every dietary wish during times of illness even though she struggles with obesity). There were periodic seizures in her teenage years. She got married and divorced (10 year period) and we heard of one potential seizure during this period, which she said prevented her from hosting a family event she had arranged (the work fell to me and my parents while she lied down). Her second husband is very caring, to the point of indulgence with his own children. He was previously married to a woman who is "scamming the welfare system" (my sister's words), working under the table, getting her food from a church, which makes me think he wouldn't see someone lying if it was right in front of him. Over the last several years my sister has begun to bring up epilepsy every time I see her. She insists her epilepsy is stress induced, specifically induced by talking to me. She says she cannot drive whenever there is an option of her being driven (yet continues to have a license and drive short distances). Most recently she insists she must be with her husband at all times because he is the only thing that prevents her from having a seizure. (I witnessed what he does to achieve this: he rubs her arm and says "it's ok it's ok"). So she makes him go with her most places. There are also many occasions where she says she is sick (like a cold) and needs to talk about that extensively and does not react well if I don't participate in the conversation. She committed to babysitting for me while I went on an anniversary vacation then said she couldn't because she was starting a new medication and needed 24 hour a day supervision (her husband works full time so it was unclear how this could possibly be achieved). We cancelled a trip of a lifetime that had already been paid for and she did not apologize and instead went to my mother to say I was not being kind about her epilepsy. Her last 72 hour EEG was negative. She claims her neurologist said her seizures are "too deep in the brain" to be detected. Recently our mother died. Our mother was her main source of attention for her epilepsy. She has now said that I don't care about her epilepsy and it will shorten her life. When I didn't respond as she wished (which was to say she should work on getting enough sleep, not drink alcohol, adhere to a keto diet for epilepsy). She said she never wanted to speak to me again. So I guess we are estranged now. But I am listening to a podcast called Nobody Should Believe Me and it is making me think my sister has some sort of factitious disorder, albeit based partially in reality because she does have a diagnosis of epilepsy. I am wondering if this sounds like Factitious Disorder and if so should I just give up on her? She is basically intolerable, my husband cannot stand her behaviour and I don't see a way forward if she has a mental health disorder that she would never admit to having. I am lost and confused. To be clear my life is better without her attention seeking in it but I do not feel good about it.