Inexcusable. I own a business too but when stuff happens, even something dramatic as a death in the family, I've always made sure to keep my clients informed myself or via proxy. It's not hard- detailed out-of-office email responders, mass emails, detailed voice mail greetings, ect. Stuff happens, but once you take a person's money you still have some minimum obligations you must fulfill.
I wish the best for his family situation.