For anyone who has been wondering, I recently located someone who personally knows Fischhead and asked her to pass on my concerns to him.
apparently Fischhead is fine and okay and alive and nothing terrible happened to him.
This is the exact text from my contact (with identifiers removed):
"Hi, just wanted to let you know that G*** ['Fischhead'] is doing fine, he’s just kind of a goober who isn’t very good at maintaining communication from people. My husband still gets random texts about video games from him from time to time, so I will have him pass your message along."
So there you have it: Fischhead is officially a Goober.
When he gets back remind him of this fact, welcome him loudly, and beg him for free commissions. He owes us!