Help. Need advice on what to do. - long

So I am 15 weeks pregnant, the father of my baby decided in July a few days after I told him the news that he doesn’t want me to contact him without a lawyer, as he doesn’t believe that the baby is his (it is, no doubt about that). He’s blocked my number and no longer has a Facebook account, etc.

so far, I’ve respected that.. BUT I got my generic screening results back last week and my two choices are

A- he needs to get tested for a developmental disorder that I am a carrier for (it’s recessive so both parents need to have the gene)

B- get an amnio to see if the baby has it.

Obviously I’m trying to avoid the amnio due to risks to the baby, but I emailed him (as that’s my only other way I have to contact him) the situation, asking him to please consider getting tested, and I could give him all the information to set it up. That was last Friday and I still haven’t heard back.

But.. I found his mother on Facebook a few days ago. My question here is, would it be too harsh to contact her and ask her to have him contact me?

as of July, my last conversation with him, he told me he didn’t want to tell his mom because she’d be excited and want to be involved, when he obviously didn’t.

So.. would it be too harsh? I wouldn’t be doing it to be petty, but I’m hoping I guess that a motherly push could get him to do the right thing.

Thoughts?