i have someone blocked and the messages aren't turning green anymore, will they recieve those texts once i unblock them

So I have an ex blocked who I have sent texts too for a while now. They used to turn green telling me he isn't recieveing them. All of a sudden the messages are staying blue just not delivering. I want to unblock him but am terrified he's getting the messages. I had my roomate blocked to test it out and she was still recieveing my imessages they just didn't say delivered on my end, and I wasn't recieveing her messages. Has he been getting those messages or will he get them once I unblock him. I tried with another friend and that was fine she couldn't get my messages i wasn't getting hers. when I unblocked her and texted her all the messages sent that i sent while blocked.