Hello all, OP here. Its been a while so I thought I'd give somewhat of a happy update.
Its hard to believe its been almost a year and a half since BIL passed. All those "firsts" were tough for my sister and nephew but thankfully my sister managed to dig real deep and keep going. There were a few setbacks with my nephew, sleeping habits, eating habits etc.. but over time, with some counseling and other things, they've made their way to their new "normal". One of BIL's last wishes (I have since learned he asked for this the day/night he passed), was that she take their son to Disney World. This past October they did just that, and while my sister admitted Disney "just isn't her thing", it definitely worked wonders for my nephew. They decided to go on a
Disney cruise this past March too, where he also had a blast.
He gave up the Marvel movies right after his dad passed, but I think that was because it was going to see them was "their thing" but he's slowly been catching up on the movies since then.
He's back to normal in school, hanging out with friends and all that stuff that kids do. My sister is back at work, adjusting to the single mom life, but otherwise doing well. I think for her learning how to be a dad has been a real challenge, but our dad and myself try to help out when possible.
So there you have a quick update. Started super sad, got much worse, got slightly better, and still getting better each day
For those of you going through something similar, directly or indirectly, you have my deepest sympathy. Once again and as always, thanks for taking the time to read along!