Muslim ibn Aqil
Muslim ibn Aqil al-Hashimi (Arabic: مُسْلِم ٱبْن عَقِيل ٱلْهَاشِمِيّ Muslim ibn ʿAqīl al-Hāshimīy) was the son of Aqil ibn Abi Talib and a member of the clan of Bani Hashim, thus, he is a cousin of Hussain ibn Ali. The people of Kufa called upon Husayn to overthrow the Umayyad dynasty who was on his way to Mecca for the Hajj pilgrimage. He wanted to confirm the loyalty of the people of Kufa, so he sent his cousin and his ambassador, Muslim ibn Aqeel, a famous warrior, to Kufa to observe the situation.
According to Amaali al-Shaikh al-Sadouq, Janab e Muslim ibn Aqeel (AS) had two sons martyred in the day of Ashura with Imam Husain (AS) and another two sons who ran away from Karbala after the martyrdom of imam Husain (AS). These two sons where martyred later on after Karbala and were buried near Musayyab in Iraq. أمالي الشيخ الصدوق
Muslim Ibn Aqeel (AS) was born in Madina in year 12 Hijri and was martyred in Kufa in year 60 Hijri by Bani Umayyah as he was the envoy of Imam Husain (AS) to Iraq. His age when he was martyred was 48 years.
There are many books on this subject in Arabic and Farsi.
You may ask Urdu speaking scholars whether such books were translated. You can also ask the Masjid al-Kufa shrine