Over the Rainbow Bridge
I'd been thinking about Mookie a lot the past few days, so last night I wrote to Kay (the vet) to check in on him.
She replied that he had developed rapid onset dementia like symptoms and started having seizures, which seemed to indicate a brain tumor. Because she was not able to fully control the seizures and because of his advanced age (almost 12, just about the average life expectancy for a Boston), she had made the hard decision to put him down.
Not exactly sure when this happened, because she wanted to spare us the grief and pain and didn't tell us.
R.I.P. Mookie 1/1998 - 10/2009