"Since your post on the S Court taking on the case about conversion bullshit, I have suspiciaon my younger brother was given something to stop him from getting hardons even tho the antigay camp sais no, they told him it was simple retraining of thoughts.. Can you really stop your dick from getting hard just by thinking? Is there any longterm residual effects of chemical castration cuz he still can't get hard?"
First of all, I'm sorry your brother was sent to one of those places. They're awful. They don't work. And they can cause long-term damage --- mental and physical. I'm glad he's got someone he can confide in.
The answer to your first question is, "No." You can't stop a boner just by wishing it away.
Erections are a normal physiological function, and a normal response to any form of arousal. The function is important to overall health and well-being.
According to the Cleveland Clinic, there can be long-term residual effects, depending on how long the medication was used. Low libido is common - which, of course, has an effect on getting hard. That, in turn, can often cause depression. Other physical issues can also crop up depending on length of use: like weak muscles.
If he was given any kind of medication against his will or knowledge, or without the knowledge and written permission of his legal guardian, those conversion camp folks are in some big trouble. I'm not sure how long traces of the medication remain in the bloodstream, but you might encourage him to see a doctor.
If that comes back positive, it's time for lawyers. All of that is, of course, dependent upon who his legal guardians are and whether they care about his well-being.