I work pro-bono on a product that is in a beta phase. I'm doing that alongside my regular job and it's fair to say I'm stretching myself thin as it is. As such, there are naturally going to be some problems but I try to fix them as soon as possible. Recently, after figuring out one of the problems was due to a (pretty rookie) oversight by me, one of the more senior people who use the product sent me an email which I will translate here (names and unimportant details are changed, but I tried to capture the tone of the message to the best of my abilities)
From: Peter Smith
P.S. My older son Robert Smith who will be 28 on May 17, 2017, and is getting married on June 6, 2017 is an economist and a product manager since he studied at [College A] and [College B], and is now a product manager at [link to some foreign company's site/about/team subpage] would never make such a trivial mistake.
I sent this mail only to you. Regards, Pete
For context: I'm in my thirties, graduated last year with the same degree as his son (it took me longer) and am single - all the details he knows. He doesn't know where I work now, but assumes it's not as good as his son's employer. I had problems starting my career for a long time due to health problems and only got my first serious job last year, which is also how we met - he sometimes collaborates with that organization. I have since started working at another company, mostly on recommendations from my former boss who didn't have it in his budget to keep me full-time. Even during those first meetings he couldn't stop talking about his son, but I figured that was just how he was trying to connect.
I don't know what to do about this. While he is not my boss he is important for the organization and I am working on this project as a token of gratitude to the person leading the project. I want to stand up for myself and I am quite capable of that in my private life, but since I'm relatively new to the job market I'm not sure where and how to draw the line.