I think he's humble enough and loves BYU enough that he might be willing to try.
But I'm not sure the new HC would want him there. Who wants the old boss looking over their shoulder when they take over? Who wants the old boss there when players are making comparisons and talking about the good and bad of any changes?
Yeah - I think Kalani might be one guy who could make it work. But it will never happen. I'd even say that they would be better off with him leaving for a couple of years and then coming back as DC rather than moving right into that role.
All that said - I'm still holding out hope that Kalani makes a drastic turnaround of the program and is at BYU for a good long time as HC.