He should, indeed. If he cannot use Bitcoin-qt to send the coins to an Electrum address and import them into Electrum, the best he can do is send the coins in the imported address to one of his Electrum addresses.
"Note that imported addresses cannot be recovered from your wallet's seed and therefore need to be secured separately for a complete backup of your wallet."
Read more here https://en.bitcoin.it/wiki/Electrum/Documentation#Imported_Addresses
So, it is recommended for Electrum users to use Electrum addresses because those can be restored from the seed, imported addresses cannot. Unless you have a Vanity address can only be used importing it.