Given that Killer Frost never clarified whether Earth 2 Charlie was an older or a younger brother, Season 3 could reveal that an Earth 1 Charlie existed but died before Caitlin was born.
Andrew Kreisberg’s reveal to EW that Caitlin’s mom will likely be showing up in Season 3 makes sense for Caitlin’s arc in Season 2.
Interestingly, Killer Frost revealed that it took the death of her brother Charlie to turn her mother cold.
Luckily for Caitlin fans, Flash executive producer Andrew Kreisberg has revealed that Season 3 will probably introduce a major member of her family who was only mentioned in Season 2 during a chat between Caitlin and Killer Frost.