I do know what you mean, OP. What I am about to say may make me sound like an avaricious bitch, but I will take that risk....
My mom is a millionaire. I am a single mom in my late 40s, I work full time, make ends meet (and do have a decent pension to look forward to at least). But money is always tight. No savings. Only finally bought my little flat recently, so decades of mortgage left....
I moved here to help her care for my late dad. She knows I will also care for her when she needs it, whatever it takes. No question of that. She is family and I love her.
I paid towards dad's funeral costs. I always pay my way. She is not ungenerous at all, does buy things for me and my daughter, gave me a few grand to help with my moving costs etc. She is a great mom and I am not complaining (well I am a bit, but....)
Sometimes, I won't lie, I think how very much easier life would be if I could just have a little slice of what will come to me NOW, when I really need it.
But, things are as they are. I understand that she feels vulnerable and the money makes her feel safer.