Glad he's home. But this sentence makes no sense. What's a "nuclear scientist," what are "laser-guided weapons techniques" and why would you want one to work on the other?
I can guess. A lot of work in high energy physics (nuclear scientist, see) has to do with lasers, for their direct effects or sensors/instrumentation. One has to illuminate material being bombarded in a cyclotron of similar device with lasers, and design receivers for the bounced light, and etc. Lasers are very useful things.
Advanced laser guidance systems, or simpler stuff like laser rangefinders, need things like receivers for ‘bounced’ laser beams too. I see a pretty direct connection.
Ukraine produces, or produced, until the disruptions of this war, several weapons systems with laser guidance. They were probably working on others. One of them for instance is the well-known Stugna antitank system.