You can't really call it a willing cuck due to the fact that he wasn't aware of it from the start and they had no idea that he would go along with it. After all, most people in that situation would not go along with it and would feel completely betrayed by their supposed friends.
The only reason Jason is that "close" to his family to begin with is thanks to the involvement of the MC and Lileva/Cherry.
You also mentioned somewhere that Cherry hasn't gone evil, however it certainly feels like she is leaning more on that side based on her dialogue and actions. She is literally screwing about with those close to him (especially Jason and his family).
You also mentioned that Cherry is simply trying to prevent him from being a passive bitch and controlled by Lileva (or whatever her name is), but it feels more like she's she's trying to control him too (that is how it comes across, whether that was the intention, or not).
Nobody called him a willing cuck, we said she willingly cucked him meaning SHE was the willing party not Jason.
She has no feelings for Jason but none of them have any control yet.
Cherry is trying to get the MC out of Lileva's control which means she needs to push him. Cherry isn't controlling him she's trying to put him in a position where he has to chose.
She said, right at the start of the update, she'd do anything to protect her dad but he's been fucked with by Lileva before Cherry could do anything now she's trying to get him out of it.
You have to remember Cherry does not give a single fuck about anyone else other than her dad. She doesn't care what happens to them.
She's not evil but she doesn't have many options. If she was evil she'd be killing people rather than trying to help.
Dev has already sad what happens on the path where you make Cherry evil and that's when she starts killing the girls. It might come across like she's controlling him to you but that's not what I see.