I typically buy 85/6 when at their lowest and then just sell when they rise, nothing flashy but it's guaranteed coins. The window for that has closed, was picking up 85's at sub 7k last week so just going to sell when they reach a price I'm happy at.
With the way they've killed off leagues, MM, UCL MM etc it's harder to make easy, fast coins. Easiest way is just to get as much liquid and then mass invest in fodder rinse and repeat.
Saying all that doesn't help you now but if he's struggling to catch up the foundation players, especially the Dutch ones are great and still are firmly on the power curve.