I prefer my saddles to be just leather--- no padding, no plastics, no fillers nor additives, just 100% organic built on a steel frame. My order of preference would be Brooks, Ideale, Wrights, Belt, and then Middlemore. I'm over 50 and heavier then your Dad.

This old Brooks (at least 30 years old) is on my 2003 Cannondale Comfort bike. Your Dad would be hard pressed to damage this bike. It's a blast to ride on the pavement, dirt roads, and MUPS. I'm not one to do any single tracking.

You are a swell rider to help your parents find bikes. Way to go!