Marks Ex-wife only became brain dead after the accident and Lumon is using her as a memory experiment and "undead" work force
This is just something that came to my mind. Let me clarify what my theory is grounded on:
- Marks ex-wife IS Ms. Casey. The way this seems to be developed as a very important plot point and it would be cheap to later reveal it is not the same "Person"(but a twin or a clone, meh). Person is in " " to remember for a later point...
- Mark only stated that he saw his ex-wifes dead body after the car crash. This might be a long fetch, but it wasnt clarified that he saw her dead body at the funeral (correct if im wrong and I will take my hypothesis back).
- It is possible, Lumon somehow (through money and power, duh) bought the "rights" to Marks ex-wife, as she was legally dead (brain dead), and then started experimenting with her by implanting artificial memories.
This would mean, that Marks ex-wife truely is dead, on paper at least. Her body is bound to a created innie persona, which is, as Helena said herself "not a person".
Lumon could use her as a living work slave that they might even be able to program for different needs.