If your colleague wants to try, he can call MP and put in the request. They may not allow the request as these are Z fares, but you never know until you try. If you don't get the upgrades, the SWUs go back into his account. No harm done. The only restriction that your colleague will have is that he won't be able to reserve the SWUs for a future flight until you fly and don't get the upgrade (assuming that you don't get the upgrade).