I recently experienced doing this for my father-in-law. He's the father I never had, frankly. I say 'experienced' because I didn't realize I'd need to that day. He was sundowning from a panic attack during a visit at the rehab center, and both of his child and I were comforting him. I'd always seen him as the king of the family, but there I was, rubbing his shoulder and reassuring him that he was with family who love and support him, that he wasn't lost, and that him expressing how he felt only brought us closer to want to help. That there was no shame in what he was feeling. Realizing this fact was bringing him to tears. The more he's comforted and assured with compassion, the more we get him back. What he has seems to be so heavily linked to decades of anxiety and cruelty drilled into a man held hostage by threats and his one-sided affection.
He'd stayed married to a covert narcissist until her death, and her constant void of demand drained him nearly to death trying to support it financially and emotionally. He thought that any day, surely, she'd see everything he did to show her what goodness does, and she'd at last tell him how thankful she was and soften. Her kids wanted the same, desperate for a mother who never existed within her. But nothing, right up until the end of her bitter and hateful life. He grew up with abuse and then married an abusive woman, men telling him "happy wife, happy life" and "eh, all women are nuts like that." She further taught him that everyone was was looking to take. Everyone wanted something from him. She was his main learning experience of this, and she should have been the one person he could confide in when people were abusive to him, someone to give him strength. But no, when he confided, she called him a f*ggot and a pussy. Something was bound to break.
But we're getting him back, a little more each week. As long as he knows we're here for him and that he's genuinely loved by the children he has, I really feel that's pushing something in him to come back, and he's trying harder to heal since the little breakthroughs started. No more being screamed at, called names, put down just for trying, as his wallet's drained of every drop. No more fear of the phone ringing. No more fear of bill collectors. We're honestly relieved she went first. Otherwise, we would have been her next target when the money dried up and the medical bills started coming from her self-neglect, and he would have died miserable and abused to the end. This is his second chance, if things improve, and they're improving.
It's baby steps, but we're going over all the abuse and letting him know that from start to finish, he didn't deserve it, telling him it wasn't right how father/brother/wife treated him, and today, it's going to be different, better. Each time the stress of his life is addressed, and he can vent freely about his feelings without shame, it's like a deep ooze that drains out is washed away and leaves him a little more whole every time.
This was long, but you struck a chord. It's very true what you said. Be the parent, or comfort, they needed from the beginning but never had. I didn't think so many decades later, such wounds could be healed, but first hand, I now know they can be. It's such an uphill climb, but even someone so trained never to show the deeper, honest emotions can be helped to bring it all out bare, to where it can be washed clean to heal.
And I have to say that it's also thanks to this subreddit that I know certain healing phrases and terms to help him and others realize what she put him through was truly horrible abuse. It's like his feelings are suddenly validated and permitted. I know the feeling. This subreddit is so incredibly helpful that saying so doesn't even sum it up.