How do I handle and care for my Narcissist elderly Mother and still be caregiver to my disabled twins?

Why try? Make some other arrangement for Mom and concentrate on your children.

You can’t. Mother will need a facility.

I care for a cherished 3 year old grandson with a physical disability and also for a 90 year old AL resident, and I am involved nonstop, EVEN THOUGH neither live with me.
If mom is cognitively intact, look for a nice nearby AL.

If mom is NOT cognitively intact, look for a nice nearby AL.

Remember that since you already KNOW that your mother may explode, you can be ready to steel yourself to disregarding her howls.

You can't. Chances are, at some point, you will become ill or exhausted or both. You must take care of yourself first, otherwise you cannot care for your twins.

Your profile states your mother has mobility problems. I infer your mother has her mental faculties. If so, she needs to take care of herself. She can figure out her options. She can contact agencies for assistance.

Step back and don't allow her to dump her issues on you. It's her circus and she needs to control her own monkeys.

Be good to you, southerndove!

No question about it, place your mother in a home and concentrate on your children.