This is my big interest right now. LE seems to have concluded that he's not in the swamp. He has not been at the house for quite a few days (perhaps many days).
I would like to know the answer to. your question as well. So far, there have been no formal charges filed against BL, I think LE will wait until after tomorrow's autopsy (which hopefully will conclude with a manner and cause of death). Then they'll file charges in Wyoming and BL will officially be on the lam.
His attorney cannot help him evade an arrest warrant, but I predict he'll claim not to know where Brian is.
Since the van was at the parents' house, I do believe they can be charged with obstruction of justice if they don't at the very least say when Brian arrived and when he left.
I do wonder if the federal warrant included the parents' electronics (possibly not - that may come in the future though). This is truly a bizarre case, with many twists and turns still to come.
Right now, all I feel is grief for Gabby. I don't know what the count is for DV survivors here on this thread (last I saw, there were 6, which would make me #7). When I was 22, I was still 14 years away from making my getaway.