Trailer Park Owner Bullies Elderly

My step parents live in a trailer home which they own but lease the land. My step mom turned 80 and wanted a small deck put on and enjoy the peaceful times. So she had a small deck and the park owner wants it torn down and back to a small step way to their door. She’s got quotes of 5000 or more to do this work and is devastated. The owner is a bully and making their live so stressful. We want to help her but the owner refuses for us to do it. Can you help?