Can I give consent to a vehicle search if the vehicle is not mine?

I was leaving my friends house when two police officers blocked me in, and searched my mother's car. There was nothing illegal in the car and they had no probable cause that there was anything illegal in the first place. They said if I didn't give consent that they would call a drug dog to go around the car. Ithe was already late and I wanted to go home so I let the search it.