Improve envelope greeting

I think we typically use ? for boolean fields (and you did below), so should be `.deceased?` Also, I think I understand the logic here, i.e. the primary person and spouse are either both alive or both dead OR there is no spouse and the primary person is alive. If that's my correct understanding of it, could you either add a comment that explains that or re-arrange the logic so it's a bit more obvious at first glance? This could be just an opinion but I found myself having to sort of work through the cases in my head. It's a clever conditional though :)