If you raise the issue, there may be repercussions, and there certainly wont be a reward.
Therefore, if you really want to raise the issue, do so anonymously:
- Get a one off gmail account.
- Gather anonymous evidence of coworker making up verifiable lies regarding kids, wife.
- Remove all metadata from any attached files/images.
- Stick to the facts, even if it means you have to let go some of the claims you want to make. "He takes the time off to go home and play video games." is the kind of thing that has no place in this email.
- Have a friend rewrite the email to remove "tells". Your personal style of writing will remove your anonymity.
- Never use the one off gmail account to send an email again. Do not read any response the business sends you to that one off gmail account. There's nothing useful they are allowed to tell you in a response.
Informing the business about your concerns is the secondary reason for sending this. The primary reason is to provide closure. If nothing happens afterwards, you are now assured the company knows and accepts your coworkers actions, having more information than you do.
Finally, who should you send it to? You do not know the whole story, so sending it to all his teammates or even the entire company will be inappropriate. I suggest sending the email to the following 3 people:
- Direct superior of coworker.
- Lowest level HR person who's responsible for coworker.
- Highest level HR person in the company.
If you want to use a minimal version:
I'm troubled by 'John Smith's use of stock photos which he shows around the office, falsely claiming they are actual images of his wife and children. It damages my ability to trust him, which impedes my ability to work with him. See attached images.
Sincerely, A concerned employee.