If you have an illness of any kind, making yourself an island is a bad thing to do. There's a hierarchy of needs consisting of companionship, food, and more physical appetites.
I consider myself a piss-poor patient. I get grumbly and irritatable if I'm not able to do things for myself. Even when healthy, those who seemingly doubt that I can boil water for pasta, remember to make a cup of tea (and I have a particular ritual for that: Quality tea, a tea kettle, and long steeping times.), or indulge in solo activities. Life is a risk. You can die in a bathtub, (Having had an episode in one, I realize that this is no hollow, trite fear.), or you can die doing something worthwhile. Or, Live.
If you care for an independently-minded person with any one of a number of chronic illnesses, some of which can lead to increased anxiety or depression, then your job is this:
1)Teach them NOT to fear. That you can be trusted. That they can come to you.
2)Understand that sometimes, laughter is the only thing they have at that moment. Gallows humor exists because we are meant to fight for survival, to rail against death. Do not go gently into that good night. Rail, kick, scream. Laugh.
3)It's one thing to care. When we love others, we might worry. But casting doubt on others, giving them lists longer than their arm span is wide, of everything that can go wrong, feeding them that heaping spoonful of fear, shoulds, and despair, is a horrific thing to do.
4)If you care for someone who has not had an easy time of it, feeding their own fears, before they can face them down, will cause them to pull away. And for very good reason. People need not be reminded about:
A:What a former spouse may or may not like
B:A list of things they dealt with, with said former spouse/ other partner/ fill-in-blank-here.
C:Piling on new anxieties for fun. This may or may not cause nightmares where innocent people are transformed into monsters.
5)For God's sake: I beg of you, don't answer for people. Don't talk every way but to.
Maybe... maybe you should simply remind them, indulge, and honor them for this: "Just be you." Remind them of the things that make them wonderful. Be compassionate about episodes, about nightmares, about injuries.
Do NOT, I repeat, NOT allow the person to hear you ask "Why did you have to do that at the store? You ruined my day!" Feeding guilt and fear does nothing to help anyone. The first step is to try to unlearn that fear and help them so they can be confident. A normal conversation should not sound like a sarcastic reiteration of "Stand By Me".
What if you're out hiking alone and have a seizure?
(What if the mountains should crumble into the sea?)
Have the person make and show you plans, medical information for wallets, ID tags if necessary. Not often will law enforcement pay proper attention to tags, to my discomfort, but you need to be there if your diabetic needs sugar and is hassled for being drunk. The same might go for your epileptic, wandering confused, emotional, and panicked by not being able to control themselves. If they cannot speak, YOU must be calm. YOU must learn to speak for them in this instance. (The only time I'd approve of such behavior. I know how I like my cocoa/coffee/tea. I know what I'm doing. But if I am unable to function and need medical care, and have no voice, then you must use my pre-planned words.) This means planning. You all need to sit down and discuss "If X happens, then you need to do Y". All should be written down, signed and agreed to.
Remember that a smile, a nice dinner, love... can make a big difference. Sometimes, you have to say, "I understand that you weren't quite with it. I'm not mad."
I think caregivers as well as patients can benefit from seeing a counselor. Some caregivers neglect themselves. This will make frustration even more likely, and far worse than it should be. Frustration is part and parcel of the experience, but it can be too much and cause a person to react differently, to show anger they previously had no idea they felt. Toxic behavior is just that. It poisons everyone.