He should use brand new ignition coils Chinese max price is 5 k for both coils and cables.
Also he should get the spark plugs inspected.
He needs 2 sets of Chinese coils to get a perfect pair.
Other solution to this problem is to get set of Toyota 2 slot ignition coils with 4 plug wire set and get it connected it's the cheapest solution also max expense 4 k with cables and yes it's the most reliable one