Why is he dodging Joowon’s questions?

But are they?

Yeah, even if they’re not boyfriends, they’re at least fwb.

a little less than boyfriends but more than fwb heehee

I think Taku dodge the q’s more due to respect for Haesoo. After all T and H never had a discussion about is ok to tell other they are having sex. Also it is the same reason H didn’t tell J about having a sexual relationship with T during that hair washing scene (J hurt his arm and H wash his hair). Especially J and T works together, unlike H other sex partner which is not someone J know personally.