You’re right to act before a fall happens, we learned that the hard way with my mom. When we redid her bathroom in Everett, we used Alta Group Remodeling, their work is on altaseattle.com. They did a curbless walk-in shower, a built-in teak bench, grab bars that look like designer towel bars, a comfort-height toilet and non-slip tile. My mom actually says it feels like a spa, not a hospital, which was exactly our goal. They also widened the doorway a bit in case she ever needs a walker. It took about four weeks, and she stayed with us during that time. Price is on the higher end, but for something this important I didn’t want to cut corners. Wishing your dad many more good years in that house.