I have yet to understand why but per the Jain philosophy it is said that Simandhar Swami is an Arihant who is still alive. He lives in Mahavideh Kshetra and as of today is said to be 150,000 years old and has a remaining lifespan of 125,000 years. Mahavideh Kshetra is millions of miles away from us in the north eastern direction of our world. There the Lord lives in a city called Pundarikgiri . Pundarikgiri is the capital of a state called Pushpakalavati which is supposed to be one of the 32 states in Mahavideh Kshetra.
Per the Jain Scriptures the Lord was born between the reign of 17th Tirthankar Shri Kunthnath Ji and the 18th Tirthankar Shri Arihantnath Ji.
Lord Simandhar Swami’s Father Shri Shreyans was the King of Pundarikgiri, His mother’s name was Satyaki. It is said the His mother has a sequence of auspicious dreams when she was pregnant with the Lord. Something which happens when a Tirthankar is about to be born. It is said that the Lord was the most handsome since the time he was born. He was born with three complete aspects of Gnan (Self Knowledge).They are :
Mati Gnan : Knowledge of 5 sense realm
Shruta Gnan: Knowledge of all forms of communications
Avadhi Gnan : Clairvoyant Knowledge
Lord Simandhar Swami got married to Rukmani Devi and later renounced the world to obtain Diksha (renouncing the worldly life).
It is also said that Simandhar Swami has a height of 1500 ft which is the normal height of any being residing in Mahavideh Kshetra.
Lord Simandhar Swami is a Living Arihant Tithankar in MahaVideh Kshetra. Bowing to him while reciting (Namo Arihantanam ) Namokar Mantra is a good practice. The 24 Tirthankars who attained Moksh are the Siddh . Bowing to them while reciting Namo Siddhdhanam) Namokar Mantra is a good practice. When reciting Namo Airiyanam Bowing to all the Acharyas who have attained the supreme knowledge is a good practice and while reciting Namo Uvajhayanam bowing to all the spiritual leaders who teach us the philosophies of Jainim is a good practice and while reciting Namo Loye Savve Sahunam bowing down to all the Sadhus and Sadhivis is again a good practice.
Dada Bhagwan org has a very detailed description on Lord Simandhar Swami, if you would like to explore more.