This is the type of event which makes me very wary of using any 3rd party AddOn. Here today, gone tomorrow. If its something small that you can get away without and it can be removed without leaving a mess, no major issue. But something like an SEO product... If you had to uninstall it because it was no longer supported, your ranking in Google would get killed when all of your urls changed. Like when vbSEO left everyone high and dry.
I understand health issues, but that doesn't change the impact to users. I was just about to buy this. Dodged a bullet.