She's not a bad mom, she really does want the best for her son.
It's just her idea of what would be best for him isn't what he wants.
Her transphobia definitely is a problem, but it's not anything unrealistic, at the very least she's never out right hurt him physically.
At the very least, she's willing to at least take a shot at understanding him.
That's already a huge step when compared to other parents out there who would even go as far as kick their children out almost immediately after they confess.
Again she's not a bad parent, she's just overly paranoid of her son being treated badly by people, and way too traumatized of her past.
She needs to understand the way she sees this issue, isn't how everyone in the world sees it.
And she needs to understand her opinions should not be forced on anyone.
If she could accept that, then she genuinely can be a great and supportive mom.
It sounds so simple, but just like real life, sometimes the easiest answers are the hardest to understand and accept by people.