[trainerstar3]

Reposting this from reddit:

IMO, it seems that Taiga and Hiiro are planning on taking away his gashats/stop him from transforming more than anything else. Like before the backstory reveal, Taiga assumed that transforming too much gave him the virus + it's shown this episode that Emu's symptoms flare up after every transformation (not just mighty brothers).

Besides, it's not like they want him to die, given that Hiiro decides to not tell Emu about it so he wouldn't stress him out.