Not at all unless there's a big discrepancy (they know a lot more than you). The big advantage comes in to when you both go off and research things - making new sigils or runes, or finding out new ways to link runes, or learning interesting spells and modifying them...
Abraham will never be able to contribute meaningfully to your knowledge because his stats make him best suited to learn some common spells and focus on combat magic with a side serving of utility. You can boost him pretty significantly (by teaching him new and unique spells), but the knowledge is something of a one-way street. He'll be able to offer top-notch combat abilities to help you out, but in terms of increasing your personal power in the long run he offers very little.
Henrietta on the other hand will be able to offer a two-way flow of knowledge - you'll both be able to research unique and powerful things and trade for them.