Can you update someone else's calender without updating you're own?

Is there a way to update someone else's calender with out updating you're own? My husband seem incapable of sending a text to Sandy to do something as simple as picking up milk, so I always have to send it for him. I email him, and cc sandy "Remind Moe to pick up Milk after work at 6:00p". Doing this means we both get the reminder, but I'm not the one that needs to pick up milk. I just want his calender to be updated, not mine. Any suggestions?