On September 13, he was brought to Apollo Hospital in a "very bad shape", a senior doctor said.
"He was battling an aggressive thyroid cancer for the last two-and-a-half years. He had already undergone chemotherapy and radiotherapy and was undergoing immunotherapy," the doctor told PTI.
"We had conducted tracheostomy. He was being fed through a tube in his stomach. Yesterday, he was doing fine during the daytime, but his condition deteriorated at night and he suffered a cardiac arrest. He died around 12:40 am," he said.
The doctor said Nath survived longer only because he was "mentally tough" and "very positive".
"His cancer was aggressive in 2015 only. It just tore through his body but his toughness made him battle it for much longer," he said.
The BJP MP had won the Alwar seat in the 2014 parliamentary elections after defeating Congress candidate and former Union minister Jitendra Singh.
Prime Minister Narendra Modi condoled his death.
"Saddened by the demise of LS MP from Alwar, Mahant Chand Nath ji. He will be remembered for his rich social work. My deepest condolences," Modi said in a tweet.
Rajasthan Chief Minister Vasundhara Raje also expressed condolences to the bereaved family members and said it was an irreparable loss to her and the entire BJP family.
He will be remembered for his contribution for the developmental works, she said.
Nath was also the Chancellor of Baba Mast Nath University in Rohtak. His funeral services would be held today.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)