What version of Lightwave is it that you inherited?
I just found some 5.0 or 5.5 manuals the other week, a bit damp from their sojourn in the shed but they should dry out okay. Should be mostly relevant for V4.0 onwards.
Heavy buggers though. Maybe I could scan the important bits if you show me a genuine LW 'About' requestor.
I'd avoid JaxAnim. He's spent the past decade selling pirate copies of Lightwave in MicroMart. I doubt you'd get anything from him without a pricetag on it. I think he's on perma-ban at Amibench now.