I have never played hockey, so I may be totally off here, but to me it looked like Eichel was trying to stop or at least slow down and in the process his right skate made contact with Hughes' right skate and they both ended up losing balance and crashed into the boards. Hughes got the worst of it and the injury is of course extremely unfortunate, but it wasn't a malicious play by Eichel, and I am not even sure I would call it reckless, though a case could probably made for that.
I hope Hughes recovers quickly and most importantly fully.