There are some reasons why someone might not be able to medically transition, like having a blood clotting disorder (so no SRS) or a medical condition that could get worse if they take hormones (Hormones can cause issues for healthy people, let alone someone with a physical condition)
But they could still cut their hair short, wear a tailored suit and look for work looking presentable while still being true to their gender. For MTFs it's harder, but long hair isn't seen as weird like it used to be. There's other feminizing options like electrolisis or waxing, and contouring makeup.