Switzerland with elderly parents

Hi all,

As the headline indicates, I am taking my parents to Switzerland. It is quite last minute as my dad is losing his eyesight but has always wanted to see Switzerland. I have taken all the measures I can think of to make getting around as easy as possible (Swiss pass, jungfrau pass, staying next to stations, staying in Lauterbrunnen rather than Wengen etc), I was just wondering if anybody else had been to Bernese Oberland with people with mobility issues, how they managed and any advice they may have?

Thanks