adding sleep 1 is unreliable (it really depends how fast/slow is the
hardware) as you can see in debian bug #908796

the fix was to add --notify-await to start-stop-daemon without any
additional sleep

if eudev does not implement the notify protocol, then i think it should
be started with --daemon paramenter, but this could bring back the
debian bug #791944, in case eudev does not remove the control socket on
stop or if it does not creates a pidfile

in that case a new init.d script should be written to remove the control
socket just after sendsigs, in order to fix the device-mapper/cryptsetup
shutdown issue

you can see more proposed fixes/workarounds in the bugs linked, but i
give some can help if needed

ciao!