Consequences of online trolling ?

If he is visiting sites that are full of such obnoxious behavior he is likely not going to get into trouble. likely it is his outlet for his frustrations.

The biggest thing you can do for him is to encourage him to see a counselor, though its possible he has been to so many that he doesn't want to see any more.  Also if he is high functioning he may be telling the counselors what he thinks they want to hear instead of what he truly thinks or feels.

I don't know your religious beliefs, if any, but it might help to take him to a brothel, let him get laid and let him learn that the opposite gender is not a strange other world being.

Hard to say. Depends on how you handle it.

Encourage him to go to a therapist. It seems like he need helps from expert.

There are some people you can't get to.

Let him get in trouble.

I have Asperger's myself and your friend is perfectly capable of knowing right from wrong and the consequences of his actions. I was also abused as a child and bullied in school and I don't feel the need to take my anger out on others. His ASD is no excuse for his behaviour and you need to consider whether you should continue your friendship with someone like that or even report him to your local police via their website.

You could tell him that he has a choice between continuing to be a disgusting piece of work or you'll walk away. Also tell him that his behaviour can easily result in prosecution and imprisonment. Punishment is up to 15 weeks in prison and a fine of up to 700% of his weekly income.

''Malicious Communications is where someone sends a letter or any other form of communication that is indecent or grossly offensive, threatening, or contains information which is false or believed to be false. The purpose for sending it is to cause distress or anxiety to the person it is sent to.

An offence of Malicious Communications occurs as soon as the communication is sent, and does not even have to be received by the intended person. It is the sending and intent of the offender which counts as an offence.'' https://west-midlands.police.uk/your-options/malic...

He is lashing out at random people for what he perceives as payback for all the yrs that people have lashed out at him.  Him mind is not right & they often times develop harmful Psychological behavior.  He may not be able to distinguish good from bad. I don't think logical reasoning will stop him.  His mind is twisted & he doesn't see the wrong in it.