Relapse and you didn't feel comfortable safe being honest open with him? Sounds like my dad opening up to him and being shamed.  It seems your entire relationship with your dad was based on a lie you told him since the age if 11. Is he is treating you based on what you lied to him about? If so he is treating you normal as someone without a stutter and thinks you're quiet. My dad knows I stutter but he doesn't believe mental health trauma exists so that's my story. So I can have surface level conversions and babble like a baby and not be shamed for it. But once I try to mention anything deeper, since he is also traumatized and doesn't understand it, he is mentally not ready to talk about deeper topics. Is your dad the same denying mental health exists? I assume this because you as an 11 year old subconsciously and consciously didn't feel safe enough to truly Express your honest feelings and lied about being cured not talking about relapse so you don't disappoint your father. Healthy parents should have properly raised their children good enough where the child can unconditionally express everything on their mind. If parents aren't willing to love their children as much as they safely can, then the love was never deep in the first place. I'm almost 30, coping through life only gets worse. It's unfortunate, but if you don't find emotional support elsewhere to in order to feel mentally secure telling your dad the truth, it will only get worse. It sounds you don't have the emotional support you need from your dad at least to truly express your honesty genuine feelings. This is a widespread problem not just with older people but people in general. Get the mental health help support you need to be able to safely talk to your dad about this. From online, in person other family friends school, any kind of mentor counselor community etc. You could post this entire story to mental health type subreddits, it would be a interesting read.