I have a game with 4 Medics and 2 Supports fighting Hans.
I also have a game of 3 Medics, 2 Zerks, and 1 Support fighting Hans.
Both on Hell on Earth of course. I have them both recorded on the last wave and Hans fight, but I only have one uploaded.
Anyway...
Medics seem to work fine versus Hans as long as they have at least one heavy weapon. Either they sacrifice their MedAR and get an AA12 with the MedSMG, or they keep the MedAR and get a Pulverizer.
The general idea is to keep circling him like any other difficulty while everyone else shoots him. The Medics of course keep each other and their teammates alive and preferably drop healing grenades on Hans and his target when he heals.
Also on HoE you have to look out for Bloats and Sirens, because Hans can spawn them.
Generally because of how unfair Hans is without the circling bug, and how insanely easy he is with it, it doesn't matter how many Medics you have as long as you have at least 1 to heal teammates and to max a teammate's armor while Hans drains his health.
Any other questions about Medics? Cause I have tons of experience on the subject.