Fluvoxamine

I'm trying to find a good medication for my seventeen-year-old autistic brother. He is generally happy and cheerful, but his arousal state is very high. He has low pragmatic language, poor impulse control, and difficulty pushing through "transitions" (e.g. getting into his clothes, getting into the house). If I don't do things "on his time", he can become aggressive. He also becomes aggressive when forced to say "Goodbye" to adult strangers who are male right after meeting them, which he feels the need to do over and over again, yet becomes upset when presented with the opportunity. All these anxieties can build up to violent outbursts. I often find myself fearful being next to him when I can tell he's getting worked up about something.

I've been told by his psychiatrist that fluvoxamine may be appropriate for his compulsions. However, I'm finding online that it can result in a battery of long-term side effects. Because he has poor pragmatic language, I'm afraid that my brother cannot give feedback.

Does anybody have experience trying this drug on their kids, and if so, how did you find it? Was it effective? What dosage did you try? How did it change their personalities, if at all? I don't want him to feel loopy or drugged up, because I'd like to surface his real personality, which is pleasant and good-humored, rather than suppress it.