It's a common excuse yes, but be sensitive. It just may be true.
In fact, last year when my dad died, I had to email all my buyers that there would be a delay in shippings for a week or two. The outpouring of sympathy was amazing, and nobody gave me a hard time.
So just be careful how you treat the situation. I typically follow non-paying reporting at close to 4 weeks on this situation, after a follow up email at 3 weeks. Since it doesn't happen often, it doesn't muck up the works.