Thinking as I type here ... if he is determined to stick around and you can't catch him to de-lice him ... is there a liquid de-licer or similar concentrated liquid available? (I use powder, so no idea).
You could fill up one of those super-soaker, giant water pistols with some and dose him from a distance?
You could fill up one of those super-soaker, giant water pistols with some and dose him from a distance?