so in the twist he found her documents where she turned out to be his mother, apparently)
If you followed the story from the beginning here on Seaside Mystery, you should have read the fact that MC's parents died in a mysterious car accident
and why MC ended up living with Carl and Brenda.
Even after the intro you get several hints while talking to Isabella what happened to his parents
and why MC's so interested to be involved into the investigation of Isabella.
This should be enough to understand that MC in 'Seaside Mystery' has nothing in common with the MC from 'The Twist'.
Janice even tells the MC here on Seaside Mystery what happened in her life before moving to Seaside.