Help My Cat Twinkle, Please!

I need some help. My family needs some help. My beautiful cat Twinkle needs some help.

Twinkle is 18 years old and is a generally healthy cat. She is small, isn't as spry as she used to be and is going deaf, but she sleeps well, eats well, drinks enough water, and still uses the litter box properly. She purrs, sits on people's laps, shows affection. So, what's the problem?

She literally caterwauls all night long. She is exceedingly loud and she sounds distressed and deranged when she meows like this. We don't know why, but it is keeping everyone up at night, which is highly problematic. It is affecting my family's health and wellbeing, and they don't know what to do. They have tried sedatives on her and it just made her worse. They've tried catnip and therapeutic touch and still nothing has made her better. We don't know what to do but my parents and sister are living with this day after day and are at the end of their ropes.

I'm wondering if anyone has heard of something like this before, or has any suggestions of what we can do to help Twinkle. We don't want to have to put her down, but we are afraid that the vet will say that is the only option if we bring her in again with this problem, and things can't continue the way they're going right now. We are getting ready to say goodbye to her, but it will break our hearts. Perhaps there is someone out there who is willing to take good care of her for us. Or maybe someone knows about other options to cure this problem.

If you or anyone you know can help, please let me know as soon as possible.

Thank you.