Why did Napoleon IV die fighting in the British Army? [closed]

Question

In 1879 in a war against the Zulu, Napoleon IV, son of Napoleon III participating in the British army met his maker. The question is why wasn't he part of the French army?

After the 1870 war his father's empire was abolished, and Napoleon IV went first to Belgium then to England. There was talk of him marrying one of Queen Victoria's daughters and the latter was in favor of it. He enrolled in some British military academy but I still find it odd that the British would let the most credible claimant to the French throne join their army.

Moreover, the Wiki article makes no mention of why he did not return to France. Perhaps he was banned from France but I doubt that. Still, I think it would have been better for his career to join the French army. Maybe the French army was in shambles after their defeat in 1870, I don't know.

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EDIT: Precisions by @totalmongot

The closing reason is unclear. The OP in the question does mention points that are not "too basic" or answered by the single wikipedia article on Napoleon IV reading. Theses points are:

• Why did Napoleon IV not come back to France?
• Why did the British let him enter their army?

First point might find answers easily by googling, but not the second point. Because the second point is answered by the evolution of geopolitical context during 19th century, which is typically what an answer on SE could explain (since the OP is making the false assumption that Napoleon IV and Napoleon I had same feeling towards Britain).

Answer 1

What might make you feel odd about these events is that you read them with a Napoleon I point of view and not Napoleon III's one.

For the first one, England was the opponent, as before for the Revolution and for the kings of France. But under Napoleon III, England is, on the contrary, a reliable ally: Even if some rivalries still exist about colonial empires, and even if some British admirals are shaken when France launches new ships, overall, the two countries are Allies:

• They fought together the war of Crimea and they battled the Turkish fleet at Navarin
• They had the same behaviour during the American Civil war
• England feels united Prussia, with its industry, is an economic competitor, even more after the war of 1870
• They had common interests and intervene with their fleets in South America, during the multiple wars that occurred there during the 19th century

So, France and United Kingdom were no longer opponents in the end of the 19th century. When Napoleon III had to abdicate, it was not as harsh as during the Revolution: the exile of Napoleon IV was a security for the French Republic but she did not try to kill him. So England was not annoying France by accepting him on her territory, and by enrolling in her army. On the other hand, it was not a good idea to make the son of the ex-Emperor fight in the French Army as an equal (in the Republican sense) of the other officers.