Not exact but perhaps helpful, my wife had to take leave off her job, not FMLA but no work no pay for her disability. She has a physical disability for which she is now on SSI. Her parents and I "forced" her to take the time off. She was upset and frustrated with us, although she kept it simmering just below the surface. She was afraid of becoming useless and unproductive and those thoughts haunted her. She eventually came around, applied for SSI and was accepted, but it took two years. This was twenty years ago. She grew up "going out" for on reason or another, so being at home is difficult for her, but she is surviving. Sometimes she gets so discouraged she sits in a "house of projects". We counted one time and she had started 77 projects and never cleaned up/finished the first one! Through the entire house one could not step without needing to be careful of stepping on something.
Please encourage him to talk and be an attentive listener, repeat what he says and allow yourself to feel his discouragement and his fear. I recently confronted my abusers and my wife said the most poignant thing to me, "My little girl wants to come over and hold you hand" referring to the hurt little boy she had seen in me after the confrontation. We hurt together and we heal together.
My best to you,