Help! Buying My First Project Car

If the car "belongs" to his sister. I'd be negotiating with her to start. There is no absolute answer here for you. Each state has different requirements. Heck some states don't even worry about titles after the car is X number of years old. In some states the car can be stored for a period or worked on and then a mechanic's lien can be put in place and the vehicle transferred basically as abandoned. The hopeful way to handle it would be to get the sister to file for a lost title, sell you the car and sign said title over to you. Good luck.

Just as a last word of caution. You are more likely to get bit than have an easy outcome.