My partner's BIL is going to meet our daughter for the first time in a couple of week's time. He's got some deep mental issues which often see him having psychotic episodes including hallucinations, etc. He is heavily medicated and often has to be admitted into psychiatric wards because he has made attempts to commit suicide. He is yet to be properly diagnosed, but bounces between being labelled schizophrenic or extremely bipolar by different diagnosticians.
I find it difficult to be sympathetic at the best of times, as much as I logically try to rationalise that he can't help his behaviour - there's just a mental barrier stopping me from understanding. Sometimes I want to shake people who struggle with mental difficulties and say "snap out of it", even though I've had plenty of my own depression and know it can't be controlled.
The reason I don't want him to have a relationship with my little girl isn't just because I think as he isn't in control of his actions he may do something bad. I've seen the way he conducts himself around my other BIL's kids (his nephews and nieces). He spends most of the time he's with them trying to discipline them - literally screaming and shouting at them for things which aren't even necessarily bad behaviour (e.g. if he kicks a ball to them and they pick it up to throw it to him instead of kicking it back). It always takes all the strength I have to stop myself saying, "calm the hell down" because it isn't my place, and nobody else says anything either. This isn't the way I want my daughter to be raised and I know he will be the same with her. I don't really think it's anyone's place to discipline my child apart from mine and my partner's, and maybe her grandparents.
I feel really guilty for using his anger issues as a reason to try and stop him from seeing his niece. My partner doesn't even recognise there is a problem, and I don't really dare to talk to him about it because I know he adores his brother and would probably think I was trying to be too controlling - and I understand because if it was the other way around and he wanted to try and limit the amount of time one of my family members spent with her, I'd probably be a bit offended too. But my family are always very cautious not to do anything they aren't 100% sure I would appreciate. Whereas BIL doesn't have such control.
Am I right to feel as guilty as I do about my concerns?