Q: iPad Blocking Vs. iPhone Blocking?

So I have both an iPhone and an iPad. I was just wondering, if someone blocks your phone number, does this also prevent you from messaging them using your iPad, since the person receives it in a different file (with an email address instead of a name)? My boyfriend blocks me when he gets mad and I was trying to see if I could still contact him. I sent an iMessage from my phone, and it said "delivered", which means nothing because you still don't know if you've been blocked. But when I sent an iMessage from my iPad, it never said delivered. It said nothing at all. His phone number is the only one that my iPad won't deliver to. But I thought if he had my iPad blocked too, it would still say delivered. I don't know. Ideas?