I don't think it's erasing Chris' autonomy to expect the show to address both his understandable anger with Eddie and the possibility that his grandparents are exploiting that anger for their own ends. Their desire to keep Chris in El Paso, with or without Eddie, has been a source of conflict from the very beginning. It would honestly be a completely bananas narrative choice to ignore that entirely.
Not for nothing, Helena's behaviour towards Eddie during the call was a big flashing light that something is not right. In particular, her offhand comment about putting a pool in for Christopher, along with Eddie's reaction to it, tells us two super important things:
She intends Chris to stay with her for the long term, maybe permanently, to the point of basing major financial commitments and lifestyle decisions on it
She has not discussed this intention with Eddie and she doesn't feel like she needs his input
It's SHADY. The absolute best faith interpretation is that she was being thoughtless to the point of cruelty for bringing it up in such a casual way, focused so much on her joy at having Chris with her that she's oblivious to Eddie's feelings. I mean, compare Chimney's much less egregious comment, "I've got two kids at home." He immediately realises how this might be hurtful to Hen, and corrects himself to emphasise that it's only temporary and Mara will be back with Hen soon. Helena could have added that a pool would be a great reason for them to come and visit, once Christopher is back home with Eddie, but she didn't and I think we are meant to understand that this is not how she's thinking of it.
