iPhone texting all typed texts in Messages app

Hi,

My son has an iPhone 5s running iOS 11.1.

Since this afternoon, I get texts for anything he seems to be typing in his messages app. A little example:

I sent him the message "I'll be home in 10 minutes" (from an android phone, don't know if this matters)

Shortly after that I get a series of texts like

- Laughed at "I'll be home in 10 minutes"

- Removed a laugh from "I'll be home in 10 minutes"

- Questioned "I'll be home in 10 minutes"

- Liked "I'll be home in 10 minutes"

- Removed a like from "I'll be home in 10 minutes"

Could anyone help me with this issue?

I suppose it's iPhone related, as I've never seen this before and he only has the phone since a week.

Thanks

Jonathan