I suspect that is a typo and that you meant to say that she should NOT have a place in your current relationship with your bf. This person needs to be put in the past and left there. Tell your boyfriend exactly that. Tell him that you do not want to hear any references to her. She should not have access to him via social media. NONE. What is going on in your lives now is absolutely none of her business. Her life is none of your boyfriend's business.

He should make a solemn pledge to you that he will absolutely not seek out any contact with her. Furthermore, he should reject any attempts whatsoever that she makes to contact him. If people you know like to bring her up in conversation to you, then you and your boyfriend need to have a pact on that. Rehearse it before you are around people who might do that. Decide that you are going to be totally disinterested in any conversation that gets to being about her. If anyone remarks on that, just say "We've decided that she belongs in his past and not in our present. So we don't think about her or talk about her anymore." Then refuse to be engaged in any exchange about her.

If his mother wants to accept visits from her, then she is a little crazy. But put up the same barriers there. If you stick to this, eventually she'll get tired of trying to intrude on your life.