I have never fished your arae, but if ou are talking about small 30' to 45' wide streams then a Spey may not be the best option. It will work for you; just it may be cumbersom at times.
If he did good with the 10' rod that may be the answer to your question. There are many inexpensive 10'ers out there even by top manufacturers. You got him on the right path, I guess the key would be to eliminate the frustration to him.