We can give another explanation why Yitzchok was consoled through Rivka for the loss of his mother, Sara. The Netziv says that Sara was greater in Nevua than Avraham Avinu, since she was alone in the house and was: מְִּּתבתד ְּד ְּוֹ alone with Hashem, which caused her to became greater than Avraham Avinu, who was busy outside the house being M'karev people. Yitzchok was also known for Hisbodedus, and some Meforshim say that: כדְּ טזְְּּו א יש ל א י ד ע הּ no man “knew” her, means that Rivka didn’t socialize, and she kept herself pure. So Rivka was similar to Sara and Yitzchok. *****
We can also perhaps say just the opposite. When Eliezer davened to find a shidduch for Yitzchok, he davened that she should be someone with extreme Chesed. So Rivka was just like Avraham Avinu, the reverse of Yitzchok. Every match needs Chesed and Gevura. It seems that by the marriage of Avraham Avinu to Sara, he was Chesed and she was Gevura. By Yitzchok, he was Gevura and she was Chesed (especially if: ו א יש ל א י ד ע הְְּּּכדְּטז no man “knew” her doesn’t mean that she wasn’t social).
