Would you include a girlfriend of a son in the obitutary?
This is a personal judgement call. It usually depends on the length and depth of the relationship. If your son has been dating his girlfriend for a couple of months, she would typically not be included. If however, he's been seeing her for a few years for example, it would probably be appropriate to include her.
As for wording, newspapers have different wording for obituaries and death notices in different parts of the country. Here are a couple of examples that include married sons with the wording for the unmarried one:
- Mr. Smith is survived by his sons, Tom (Ann) Smith; Joseph (Heather) Smith and John (Melissa Jones) Smith.
- Mr. Smith is survived by his sons, Tom and his wife, Ann; Joseph and his wife, Heather; and John and his friend, Melissa Jones.
And don't forget to ask your son and his girlfriend how they feel about including her.
I know this answer is late based on the date you posted it but hopefully you found a way to handle this that was agreeable to all, and maybe this response will help any who read this post in the future with the same question.