Why did Bakht Khan switch sides in Indian War of Independence 1857?

Question

Bakht Khan was one of the key commanders of the Indian Liberation Forces fighting against the British for independence of India.

From his early life, It is known that he was enlisted in British Forces in India (Possibly was still enlisted when the Indian mutiny started?). He even rose to the rank of Subedar which was the second highest rank available to Indian native soldiers serving in British forces back then which means he was:

1. Capable in terms of leadership skills
2. Fluent in English which means he was adopting to British culture somewhat or at least that he had accepted to live with it.
3. At good terms with his British officers otherwise he would not have been promoted

He even fought for the British in First Anglo-Afghan war despite being an ethnic Afghan (From Yusufzai tribe) himself.

Yet when Indians rose up against the British in 1857, Bakht Khan brought his contingent of Rohilla Pashtun Soldiers to the Imperial Capital city of Delhi and decided to fight for the Old Emperor and was eventually granted the title of "Lord Governor General".

Why did he do that? He appears to have no qualms in fighting for the British in the past, even against his own Folk be it in India or Afghanistan. He seems to have never shown any resistence to the British in the past, otherwise he would not have been promoted to Subedar rank.

Yet in 1857, he rises against the British even though many Indians including the 21 Princely states of India were fighting on the British side.

I know a simple assumption would be that he was motivated by patriotism or by his conscience finally waking up. But I am looking for something he may have said in this regard or some Historian may have established about it.

Is there any reasoning provided for his act in contemporary or modern works on the Indian War of Independence?

Another Question but you may ignore it if you want as I don't want to broaden the scope. Was he still enlisted in British Forces when the Rebellion started?

Answer 1

For a possible reason, Encyclopædia Britannica says this about Bakht Khan (emphasis mine):

Related on his mother’s side to the ruling house of Oudh (Ayodhya), which was deposed by the British in 1856, Bakht Khan served for a number of years as a field battery commander in the army of the British East India Company. When the rebellion broke out in May 1857, he led his troops to Delhi, where he emerged as the dominant figure in the independent Indian government proclaimed by the rebels.

Wikipedia article on the Oudh State:

On 7 February 1856 by order of Lord Dalhousie, Governor General of the East India Company, the king of Oudh was deposed, and its kingdom was annexed to British India under the terms of the Doctrine of lapse on the grounds of internal misrule.

Wikipedia on Indian Rebellion of 1857 (causes):

After the annexation of Oudh (Awadh) by the East India Company in 1856, many sepoys were disquieted both from losing their perquisites, as landed gentry, in the Oudh courts, and from the anticipation of any increased land-revenue payments that the annexation might bring about.

Definitively not an answer, but info about Bakht Khan seems scarce (a simple Google search now returns this page as 9th result).

Answer 2

I think General Bakht Khan the Great was a disciple of Maulana Sarfaraz, who was a mathematician and a master of astronomer. Both were followers of Shah Ismail Shahid.

He advised his disciple, the General, to support the Heretic Bahadur Shah of Delhi.