Looking at Avrahom would spiritually heal people

Medrash Talpyot at Alef
-People can reach high levels from either the side of good or the sitra achar.
-If one has spiritual flaws, climbing to levels on the side of Kedusha will be hard.
-Avraham reached such a high level towards the end of his life that he radiated holiness.*
-People who were in his presents would also feel this holiness although it would wear off.

* Rabbi Nachman of Bresslev has many Torahs about looking at the face of a Tzaddik. This is similar to the concept of not looking at the face of evil people since it effects you.