Which statement about Louis napoleon is true was he the brother of Napoleon Bonaparte was he the first elected president of France was he known as a fair gentle leader or was he captured?

Two of those statements are true; see below.

1. He was the brother of Napoleon Bonaparte. -- No. He was his nephew.
2. He was the first elected president of France. -- Yes. He was the first elected president of the Second Republic of France. However, it is worth noting that there were other chief executives of the First and Second Republic who were either not presidents or not popularly elected.
3. He was known as a fair, gentle leader. -- No. He was a dictator and emperor. While he had general popular support, he was not considered fair or gentle.
4. He was captured. -- Yes. He fought in the Battle of Sedan in 1870 and was captured by the German forces led by Otto van Bismarck. He was then exiled to the UK.