"Dorothy shoved her poor mother back to Shady Pines after she married again and the 2 women she considered "daughters" abandoned her. No wonder the poor thing visited the Weston home a lot."
Quite the opposite, bliss. Sophia even went there herself briefly just to manipulate the situation during an episode of Golden Palace. She was irritated with both Dorothy and the other two GG for arguing over where she would live. They both wanted her.
We were never told exactly how she eventually ended up living at Shady Pines again, but there was no reason to assume anyone "abandoned her." Her character showed more and more memory/cognition problems during GP and Empty Nest, so it might have been for her own good, and her own decision. Remember, Shady Pines had changed into a luxury facility after it was rebuilt.
And just FYI, if Sophia were my mother in real life, she would have been back in a nursing home the same day she was caught almost bashing Rose over the head with a cooking pot. She was flippin' dangerous, is what she was!