Sorry, I confused myself with 3 different charts.
Follower chart is basically a very weak chart that likes opposing elements more than supporting elements.
If both of you like to work with each other, I guess his chart (Gui Mao DM) is indeed an output follower because he's attracted to fire combo in your chart (fire is his wealth).
Your chart, Geng Xu DM, has a triangular fire combo but it doesn't transform. So I think you remain a fairly strong DM and your chart is attracted to wood in Gui Mao DM chart (wood is your wealth).
Geng Shen DM is also a possible output follower due to water/output from Si-Shen combo. But when interacting with your chart, there is a fire punishment. What will be punished? Metal.
As an output follower, he will like wealth element the most (wood). But your wood is combined into fire and fire is his DO/7K. So, you may come across as bigger and more superior to him. Aside from the punishment, his water and your fire will clash with each other unless wood is present as a bridge (your direct boss, who has a lot of wood energy in his chart).
Is there any worry at all? Do you sense impending trouble or something?