@LHH I'm posting an actual answer in response to your comment above.
Firstly, I gathered it wasn't the actual scene. There's nothing wrong with posting your actual writing so long as you are asking a valid question (which you are) and not expecting an edit of that sample. I would change your question to use part of your own scene.
Secondly, if the repetition of 'his mother' is already annoying you, you can guarantee it's going to annoy your reader.
You say that you need to use 'his mother' repeatedly to stay true to the way the protagonist feels about her. As in, you wish to make it clear to the reader that the protagonist is annoyed/frustrated by her and this is best conveyed by constantly referring to her as 'mother'? It's a common foible, especially with new writers (I know because I slip into it often myself), to feel they need to be extremely clear about the meaning they wish to convey, to the point that they end up beating the reader over the head with it.
Readers are surprisingly adept at divining meaning from very subtle lines of dialogue and action. And you may find you do not need to hammer the protagonist's feelings home with the constant repetition of 'mother'.
I would suggest you look closely at your scene and see if his feelings are already conveyed with your protagonist's dialogue and actions. Instead of telling the reader about his frustrations with this constant repetition, try showing it instead. Convey it in his language, in the way he taps his forehead in frustration, or takes deep breaths and counts to ten (these are just examples).
She was doing it again. She was always doing it.
She said, "I resent you for even thinking that."
Ben pressed his fingers hard into his temples. "Sorry, Mom, but you did
it yesterday, you're doing it now, you're always doing it!"
His mother stormed out.
You may find there are moments when you don't need the 'his mother' tag at all, because it is very clear that she is speaking. So remove as many as you can. As in the above example, the 'he said' isn't required.
I would also leave the scene to rest for a few days, then come back to it and read it out loud. Does it still sound repetitive? Are ALL the 'mothers' really necessary or could you leave just a few in place where they have moments of real impact, replacing the rest with 'she'?
Remember that repetition sometimes has the opposite effect to the one you intend. A bit like when you say a word over and over until it loses all meaning. Instead of giving the word power by using it in one or two select places, repetition removes its power altogether.