So, I'm not sure this is worth the stress. Little kids grab things, but they tend to get bored if you ignore them. Maybe keep the sharp tools in a drawer and let him play with a spare screwdriver or something. It's just a visit, not a permanent workshop takeover.
Hannah_lewis has a point about keeping the dangerous stuff put away. I gave my nephew an old tape measure and some wooden blocks to build with. It kept his hands busy and let me get back to work.
Totally get that approach. Giving kids safe versions of real tools is actually smart. It turns random grabbing into actual play that teaches them how stuff works. My cousin did the same with a blunt putty knife and some scrap wood, and her toddler was focused for ages. That way they learn the motion without the risk, and you don't have to watch every single second. Lets everyone relax a bit more during a visit.