Oh, Skarpi, I am sorry about your mother. I hope your friend is not in pain.
I went to Iceland several years ago on a motorcoach tour. We went to northern Iceland but not to the eastern part of the country. It was a wonderful trip to a beautiful country. Now Vantage, the company I traveled with, offers a 13 day cruise. Here are some places the people will see.

Iceland Adventure: Circumnavigating the Untamed - 2019
Reykjavík • Stykkishólmur • Ísafjörður • Siglufjörður • Grimsey • Akureyri • Húsavík • Seyðisfjörður • Djúpivogur • Westman Islands