My dad lost his bike papers.

Hey there. My dad has a Royal Enfield and he lost its papers. I know many of you would suggest going to the rto office but the problem is the bike is around 50 years old (ik too old but its a beauty). My dad tried going to the rto office but couldnt find anyhting. He's pretty bummed about it. Is there any way one can get some new papers or something?