A bit late, but am just seeing this post and felt compelled to send my thoughts to you, LMR. I was on the flipside of your situation (USC who was on a spousal visa with my UKC husband when he died).
I absolutely understand the mush brain -- and the gajillion emotions that go along with it. If you ever want to talk to someone who's been through a similar experience, just know that I'm here and would be happy to connect. It's so hard, I know. As we say, "the club of which no one wants to be a member".