Thanks for posting your query to HCM.
and problem is well expected. You have said the grafts healed well.
But, still the grafted skin is like a torn shirt and you must take care of it to prevent complications. I suggest you apply barrier creams like zinc oxide
which will protect your skin and also absorb oozing. Take plenty of water and vit c for wound healing
. I dont expect any major untoward complication. he can resume to his work but take extra care of the grafted skin. He has to prevent dusty atmosphere.