oh no, im the only onw who thinks it might not be a great idea..
I think that you should meet her, and tell her face to face your side, what hes said to you, how hes treated you, HOW YOU FEEL. how you feel about the fact you left the door open to her and she has only just recently been in touch and stuff, I think getting 'mums' to talk.. in a way is a bit.. well they will both come back to you and him and pass on info which will probably get wires crossed and then he will speak to you and i just think it would end in an argument with words getting twisted. I think you should talk to her yourself.
Its nice of your mum to offer, but i personally wouldnt do it.
I think his mum needs to hear from you,
With the dna thing, well if thats his demand hes made his bed, let him lie in it. Just tell him theres no way hes being at the birth, eh doesnt even believe baby is his why would you put yourself ina n uncomfortable situation. you want 'x' there and thats that!
He probably wants to be there because deep down he knows the DNA test will come back hes the father but he doesnt wanna know he missed his childs birth, but he wants it on paper. basically he wants the best of both worlds but you know what he doesnt deserve the chance let alone actually getting what he wants!!