iPhone sent out large group message by itself

Ok. So my husband has an iPhone 7 and last night while it was dead, sent out a group message with 13 people in it (myself included).Four contacts came from his contacts, but some of the numbers were 800 numbers and the rest were contact that wasn't in his phone and numbers that didn't belong to people he knows. The message contained a bunch of emojis and random letters. The weird part is when he charged his phone and went to his messages, he could see the group message but not the messages sent from his phone, he had to use my phone to see what was sent.

I've seen other post about the iPhone sending out messages but there hasn't been a respond from Apple!

Other than this his phone functions like normal, he doesn't have any other issues with his phone. Why would his phone do this? Where would it get random numbers from? So many questions and I would really love some answers.

These are screen shots of the messages that came to my phone. I only have one contact number for my husband.