As David said, Depends.exe, which was initially made for EXEs,
works on SYS files as well. Technically, driver has the identical
structure like an EXE (both are PE files).
An interesting fact about this is that there is no way how to tell
if it is a driver or an EXE. I have seen binary which can behave
both as an EXE or as a driver, depending how it has been executed.
L.