It is a wide misconception circulated by misguided persons that Sikh Guru saved Hinduism. Their misguided belief is based on story revolving around martyrdom of Guru Teg Bahadur which is as under;-.
Guru Teg Bahadur’s martyrdom
In the late 17th century, Mughal King Aurangzeb imposed the Sharia law across his empire and an additional jizya tax on non-Muslims and started forcible conversions. In May 1675, Guru Teg Bahadur Ji was approached by some Kashmiri Pandits seeking the Guru's intervention against their forced conversions. Guru Teg Bahadur left from his base at Makhowal to confront the forcible conversions of Kashmiri Pandits but was arrested at Ropar and put in Jail at Sirhind. In November 1675, he was transferred to Delhi and asked to perform a miracle to prove his nearness to God or convert to Islam. Three Pandits namely Bhai Mati Dass, Bhai Sati Dass Bhai Dayala, pleaded with King Aurangzeb to kill them but spare life of Guru Teg Bahadur. All three Pandits were tortured to death in front of Guru Teg Bahadur. Bhai Mati Das was sawn into pieces, Bhai Sati Das was burned alive and Bhai Dayala was thrown into a cauldron of boiling water. Martyrdom of Pandits did not save life of Guru Tag Bahadur. On the orders of King Aurangzeb Guru Teg Bahadur Ji was publicly beheaded at Delhi. Today, Gurdwara Sis Ganj Sahib and Gurdwara Rakab Ganj Sahib stand at the sites of beheading and cremation of Guru Ji’s body.
The martyrdom of Brahims; Bhai Mati Dass, Bhai sati Dass and Bhai Dayala did not save life of Guru Teg Bahadur, same way, beheading of Guru Teg Babahur did not save even a single Kashmiri Pandits from conversion. Pandits never claim that they saved Sikhism even though three brahims Bhai Mati Dass, Bhai Sati Dass and Bhai Dayala died in trying to save 9th Guru Teg Bahadur.
Hinduism is spread worldwide was there 5000 years earlier, is there now will remain and not limited to Kashmir. Martyrdom of Guru Teg Bahadur did not stop conversions in Kashmir. The “Muslims” you see in Kashmir today are all converted Kashmiri Pandits. It is complete misconception to say Sikh Guru Teg Bahadur saved Hinduism or even few Kashmiri pundits from conversion. It is same misconception to say Brahims saved Sikhism though three Brahims died in trying to save 9th Sikh Guru Teg Bahadur ji. It were Brahims who gave a call that first born male of the Punjabi Hindu Family is given to the Sikh Panth to grow up as a highly skilled Warrior as protector of religious freedom and pacifist Hindus.