Freckle Laser Questions

Hello, I have a question about freckles laser treatment. First of all, I have a lot of freckles around my eyes and around my mouth compared to the fact that I have been applying sunscreen consistently since I worked outside in the middle of summer. I am also wondering if I can get the freckle laser treatment in one session or if I need to get it in several sessions. I am also wondering if it is only possible to remove freckles or if it is possible to prevent freckles while also removing them. My parents are older and have thin skin, so I am wondering if they can go out and continue their daily lives right after the laser treatment.