yes, its common practice - I also made a thread here on how I repaired my toyota 2AZ-FE with the same issue. you will need new threaded inserts made from high tensile steel. - drill it out, tap it - screw in insert. The inserts have coarser threads outside and headbolt threads inside of it. That way you use the original/factory headbolts.
I once saw an idiot machine shop in khi hammer a brass insert into the block and try to tighten the head bolt. It wont work, you need a screwed in steel insert. They are sold at tool supplier shops in Marriot rd karachi, Abt Rs 500/piece when I lived there more than 10 years ago. The tooling is separate, expect about Rs 8000 to make the centering jig etc. (make sure the drill they use has a blunt face)
The loss of coolant is a sign of a leak somewhere where its sucking air.
If the threading was stripped, how did the mechanic tighten the head?
