One of the things that's always annoyed me about romance novels featuring flighted characters is that the psychological aspects of that is generally not explored, or not explored in depth. This is actually a complex issue, and all too often authors treat 'angel' characters as just humans with wings. They are not, because a natural capacity for flight would necessarily require different reactions to things like height, space and voids, depth, risk-taking, energy demands, psychological and physical needs for social grooming, and so much more. For example, when a young bird fledges it becomes almost single-minded in its desire to flap its wings and fly. They will cheerfully throw themselves into space without thought about the fact that they are dozens or more feet above the ground. They will happily crash into obstacles such as trees and walls repeatedly and do so fearlessly no matter how much they hurt themselves because the instinct to fledge is so overwhelming they can think of little else. This is a brief, intense period and the only thing similar to it for us humans is the impetus that makes us learn how to walk. Except babies who are learning to walk are still very small, and birds who are fledging are full-sized. Imagine having to wait until you are full-grown before you can even learn to walk!
MC2 is a winged humanoid (technically not an angel, because he's mortal and not a messenger of any god) At some point in his past he was pinioned, that is to say one of his wings was partially amputated to permanently prevent him from flying. This is a different process that clipping a wing. Wing-clipping simply means trimming feathers (which will regrow unless the feather shaft is broken off in the follicle) to prevent flight. Pinioning is an actual amputation of the latter part of the wing, what would essentially be the hand if the wing is a bird's (or angel's) arm. This is a significant injury and a major part of MC2's emotional trauma. Imagine being a creature that is supposed to be capable of flight, then having that power taken away. Fear of heights takes on a whole new meaning when it is not a natural fear. I've seen parrots who had phobias of falling due to severe wing-trims--it was almost always far more extreme in them than any other type of phobia and resulted in panic attacks and severe fear-bites and self-mutilation (plucking if we were lucky, bites hard enough to draw blood and scar the bird if not) --and that's just one issue among many. Fear of being trapped is another huge fear, because he can't take to the skies if he feels threatened. As a result MC2 overreacts and over-compensates for his fears.
Then there is the issue of anatomy. Below is a labeled picture of a feathered wing, and the second picture is the bone-structure underneath. The pollex is the equivalent of the thumb, in fact it is the thumb bones. The alula or "little wing" is the feathers that are attached to the pollex. The are used to help direct flight. Then we have the primaries and secondaries, which are the major flight feathers (excluding the tail feathers which an angel wouldn't have). The coverts help with insulation and aerodynamics, as do the scapulars.
You'll notice that in this second picture all the major flight feathers are actually rooted in the bone. The feather follicle is in the bone. That means that if a flight feather is pulled out it is roughly as painful as pulling out a fingernail or tooth. Yet a naturally molted feather is completely painless. Feathers occasionally have to be pulled out because if the feather is broken while it is still growing in it will bleed copiously, and the bleeding may not stop on its own. Generally wild birds will pull these broken bloodfeathers out, but captive birds rarely do. I'm not sure what the difference is.
I have yet to read a story featuring feathered angels that actually spoke of the various problems with feathers, or their numbering, or even the difference between primaries and secondaries (not pictured here, tertiaries). Broken bloodfeathers can be cauterized with quickstop, or pulled out. Broken feathers (the fully grown in non-bleeding kind) can be repaired by splicing a new feather onto the old feather shaft. Perhaps a prosthetic could be built for MC2? People make hang-gliders and kites after all...