Spilt stay Memory Maker, early arrival

[LadyRayado]

Hoping someone can help. We're taking a large family vacation in October. My dad made all the reservations and bought a Memory Maker. I'm thinking about going a few days early with my son. I know you can use them on split stays, but can I use our family MM, under my dad's name, if I'm listed as friend/family on his account? Or will his only activate once he arrives, meaning I'd need to purchase a separate one? Thanks!

 

[LadyRayado]

An update, if anyone is in the same boat.

My first solution was to collect all the PhotoPass cards and then add them to my Dad's account once it activates. I was told I couldn't use his MM early since it wouldn't activate until he checked-in.

However, I spoke to another person at the PhotoPass tech call center who said when a MM is activated, it collects photos for 30 days after, but also collects anything 30 days before...? He said I can use my MagicBand to get photos early and they'll all be available as soon as my Dad checks in. Has anyone else heard that?

I'm curious about MM shares and how they work - does the main person have to be the first one at WDW, to check in and activate or is this the reason they work for people who aren't there at the exact same time?