

A year is actually quite a short time (in terms of deorbiting).
As for your previous question yes a collision at starlink orbit could send some shrapnel to higher orbit planes however a majority would be in highly eccentric orbits that would decay quickly on the low end.
The issue would be a starlink collision then hitting something in a higher orbit causing Kessler syndrome in that orbit. The odds of this are still next to zero but never zero.
U sure this person is who they claim to be?