What if in extremely rare cases (to the point of almost being unknown) an alpha can become an omega or a beta in response to trauma? What if when John got injured in Afghanistan, he wasn't sent home because of his limp, but because he was no longer an alpha, but an omega?
People treat John like an omega and he has a hard time coping with the huge difference. He's given over to the custody of his Alpha sister, who's expected to shelter him until she finds a mate for him. He's not supposed to do anything on his own and is expected to be submissive.
What's almost worse is the way John's body has changed. He hates his heats and the way his body craves being mated now. He has a different set of instincts he has to deal with.
John is resisting every bit of his new dynamic that he can when he catches Sherlock's interest.
Johnlock - ABO dynamics can change
People treat John like an omega and he has a hard time coping with the huge difference. He's given over to the custody of his Alpha sister, who's expected to shelter him until she finds a mate for him. He's not supposed to do anything on his own and is expected to be submissive.
What's almost worse is the way John's body has changed. He hates his heats and the way his body craves being mated now. He has a different set of instincts he has to deal with.
John is resisting every bit of his new dynamic that he can when he catches Sherlock's interest.