One idea might be RFCs. Instead of telling him to go solve a problem, ask him to investigate and write a proposal for fixing it. Add some requirements such as p

One idea might be RFCs. Instead of telling him to go solve a problem, ask him to investigate and write a proposal for fixing it. Add some requirements such as proposal should have one ideal fix and two alternatives that require less resources. Engineers want to do ideal solutions even if they are cost prohibitive. This way then you can point out anything that he missed and select a practical solution. However, ideally, you would want everyone to write RFCs for any larger project or that engineer will feel targeted.