Depends. Digital is usually best for me since I can read on my phone pretty much anytime anywhere.
That said, some books feel like they work best in your hand, like The Book of Disquiet, which has so many notes at the end and I haven’t found a comfortable enough way to skip back on forth without having to scroll through a lot to get to where I was, or House of Leaves, which is more like a fun hands-on puzzle to play with.
Is that where your phone case opens up to receive your bro’s phone into it?