He wasn't Buddhist at all and believed in the one God (Heaven, God of Heaven) in Tengrism.
Buddhism came much later with Hulagu but as did Islam with Berke Khan.
Yes the religion of most people in Mongolia is Buddhism, also for many Mongol decedents their faith is Sufi Islam e.g. Kazakhstan, and other Turkic states where the Mongols settled down.
Infact Genghis khan also attributed his success to tengri the sky god also known as the God of the Turks. There is no evidence to suggest that Genghis khan was a Buddhist especially considering how his actions were absolutely opposite to Buddhism. Infact the actions of Genghis khan was extremely brutal and who says he would have been lenient to the subcontinent. What fantasy is that?
The Mongols pursued jalal ud din all the way to Indus, burning and pillaging any city that didn't surrender to them or offered them any support. Herat, ghazni, Merv were all destroyed by the Mongols and they didn't stop there. The army if the Mongols entered the regions of Lahore and Multan chasing and pillaging despite being stretched after the fall of khawerizm and battle of Indus 1221. No unicorn came there to stop them.
And then when the Mongols attacked Kashmir in 1235 and wreaked havoc there and when they rebelled in 1251, they were put down heavily through extreme brutality. The impact was such that Kashmir remained a subject to the Mongols till the 1300s when their power started to wane in the region.
Or when they sacked Peshawar. Chalo these were the evil pashtun areas that have nothing to do with akhand Bharat. What about Lahore in 1241 and the massacres they did then. They killed indiscriminately Muslims and non-muslims and their actions assured every single king in the region that if the Mongols crossed the Indus, only death would be home to the subcontinent. Such was the impact that no Indian king made overtures to the Mongols and balban made it his policy to make sure that Mongols are kept at bay, policy which saved many states of India, since their initial target was always Delhi. Infact the Mongols made it their expansionist policy to repeatedly invade through the best and most viable route for any invasion to the subcontinent which was the way along the Khyber pass to Peshawar to cross the Indus River and invade Punjab. The sultanate made it its policy to make Indus the barrier and Lahore, Multan the fortresses against the Mongols. The Mongols continued to invade, sometimes losing, other times ravaging the region and other times getting tribute. Balban. Khilji. Tughluq all made a Mongol policy on dealing with them
Infact these C grade historians have no clue. The impact of the word Mongol such in the regions of modern day Afghanistan, Pakistan and India that Babur often cited him from Timur rather than Genghis and focused more on Timur and in his baburnama he writes repeatedly that he was not fond of Mongols and saw the name of Mongols as bad.
"Were the mughal an angel race, it would be bad, even write in gold the mughal name would be bad"
The mughal was a Mongol term and the mughals called their state Gurkani, a continuation of timurid ( who also called their state Gurkani) rather than Mongol empire. Timur was also seen as the continuous Mongol invasion.
Point is that to bring Mongols upon yourself is just as absurd an idea as to being Japan on yourself in WWII. Genocidal armies are genocidal armies.
India is undergoing insane revisionism as authors are publishing books based on hearsay or ill-gotten statements to revise history and publish a narrative. There was a book on mughal kings as well which was a long long rant on how evil they were.
So expect such madness where Mongols will be presented as reincarnation of some saviour being salvation from the Muslim kings and I am not saying the Muslim kings were playing a grand role of saving the subcontinent. Their interest was their empire however their actions did save many states of India from the monstrous massacres that ravaged half the world.
Lastly the golden horde also converted to Islam and the Mongols Islamic conversion played a leading role in Islam in central Asia so I have no idea where this Mongols were Buddhist wrath bringing Hinduism stuff comes in.
Alauddin was determined to fight to the end. As Lal describes it, he told his advisor,
“How could he hold the sovereignty of Delhi if he shuddered to encounter the invaders? What would his contemporaries and those adversaries who had marched two thousand kos to fight him say when he ‘hid behind a camel’s back’? And what verdict would posterity pronounce on him? How could he dare show his countenance to anybody, or even enter the royal harem, if he was guilty of cowardice, and endeavoured to repel the Mongols with diplomacy and negotiations? … ‘Come what may, I am bent upon marching tomorrow into the plain of Kili, where I propose joining in battle with Qutlugh Khwaja.’”
Alauddin met Qutlugh Khwaja at Kili, and the day was won by the bravery and martyrdom of his general Zafar Khan. (That the Mongols retreated because of Zafar Khan’s actions is the only explanation postulated by Barani, and quoted by Lal and Chandra; however, Jackson doubts this explanation and says the real reason the Mongols withdrew was that Qutlugh Khwaja was mortally wounded in the battle, a fact confirmed by other sources.) The defeated Mongols went back to their country without stopping once on the way.