Minor children can, in theory, sue their parents, in many countries, as long as they can prove a cognizable harm. The simplest case is where a parent commits a crime against the child, such as rape; this would also include embezzlement. "Abuse" is a term used in laws, for example RCW 26.44.020 (Washington state), but that sense of "abuse" doesn't include e.g. "overbearing behavior" or "obnoxious politics".
If a child is disabled and the parents taunt the child for that disability, it is possible that the child could sue to terminate parental rights. The case is even clearer if the parent fails in their parental obligations to the child. Lgbtqia child rights are less well-defined. The background assumption is that the parent has the exclusive right to determine the child's upbringing, which includes things such as political beliefs, religion, and matters touching no family and sex. Norway is one of those countries with relatively few restrictions on "how you live your life", and they are considering a law against "conversion therapy", but there is presently no law prohibiting a parent from denouncing their child's lifestyle. It is possible that Barnevernet (child protective services) could intervene in a particular case, but they would not sue a parent on behalf of the child unless the parents actually violated the law.