Is it possible that someone with his messenger hacked, receives hacked emails as well?,?

Probably not unless the hacker intentionally wanted that. I think you should elaborate on the situation. Does he still have his account hacked, or can he access it? In what form are the emails appearing, and what is the content?

I feel like there is something missing, so I’m afraid I can’t help any more.

Well, it looks like he answers to this mails, i think that normally this hacked mails contains something like a file to download and hack the computer, but this ones does not have any files, except for a couple of pictures without any kind of virus. What would you think?