If this student is orthopedically impaired he/she might not be able to move any faster even if they wanted to. I have lived with physical impairments all my life and I have to frequently remind people I have one speed. My body won't allow me to move any faster especially now that I'm in my late 30's. Wished more of my teachers took it into consideration when I was in school. Even with an IEP with accommodations I always had that one teacher that didn't get it and my mom had to make calls to keep me put of detention for tardies. I have students that take forever as well and sometimes you just have to meet them where they are. Take baby steps and work on executive functioning skills. Visual timers do help. I have clocks all over my house for a reason.