How does this solve the problem?

I'm becoming more disenchanted with Buddhism because as a practicioner we always have to take the high road. And does it benefit us? This whole comment makes me think of that pacture where the dog is sitting in fire saying "this is okay"

OP's mother is a burden. She talks and talks and it sounds like regardless of whether anyone is listening, she keeps talking. To top it off, if OP is not there their Mother becomes lonely. It's not a conversation if OP does not get a moment to reply, nor is listened to when they actually get to speak.

What exactly are you telling them to do? What is the advice in your post? To become comfortable with being talked at, because if you dislike an incessant talker for talking, your also dislike yourself for wanting to participate in the conversation.

I'm struggling with this practise lately. If the only person you can control is yourself, my advice to OP would be to benefit themselves. Walk away from the chatter. They're already tuning out mentally with the "mhmms", so they're just a sounding board anyway. They're being manipulated. If their Mum can't ramble on about small nothings she becomes lonely and sad. No person wants to see their Mother that way and so they continue to hang around and listen. Maybe OP should tell his/her Mum "you never let me get a word in and I am frustrated by that".

And then the next piece of advice from here would be look at why you are frustrated right? By it's own nature it is frustrating to be talked at and talked over, and not listened to when you actually take the time to speak. More so if you practice right speech and so what you have to add verbally is right.