I can't imagine you will get many positive responses in most Facebook groups.
I don't think there would be many openings for foreign construction managers in Bali. Maybe you could try contacting Populaire:
https://www.populaire.com/
There is huge demand for construction workers in Australia right now. He could try and get into FIFO and commute between Bali and Australia.
Thanks. This is the kind of thing I was thinking about, as I know his passion is for Bali. Once having experience here, he undoubtedly would want to have his own operation. After reading the numerous complaints from fellow expats being exploited in having villas constructed in recent years it seemed as if it could be a fit for this guy. It is just a matter of gaining experience here.