When Mads is released from prison, his greatest desire is to come out and be a father to his 10-year-old daughter, whom he has not seen for 3 years, but when he finds out she is deadly ill and the mother forbids him to see her , he dresses up like a hospital clown to have an opportunity to be something for his daughter before she dies.

So an ex-con can show up in cognito in a clown costume and not have to be vetted by a standard security background check before he can have regular access to amuse sick kids?

And a story about parents feuding over a kid whose doomed to die is a comedy?

We don't need names in a logline - takes up valuable words. Speaking of which, ideally a logline should be less than 40 words (ish). I'd recommend sticking this in the "logline generator" to come up with something that's a little shorter but also follows a more conventional format.

I think the idea certainly has merit but I can't help but feel like once he's got into the hospital once as a clown, that's the end of the story. His goal should be something that, the quest to do it, can sustain a 90mins+ runtime. Tricky though, as I imagine the logline for Mrs. Doubtfire was incredibly similar. In that film though, I think his ultimate goal is to legally and legitimately be seen as capable of being a responsible parent - it's only by becoming Mrs. Doubtfire does he actually learn how to do this and he also learns more about his children, his ex-wife, and himself. So what is your character's ultimate goal? He dresses as a clown in order to see his daughter but what does he try and achieve after that? You said "be something for his daughter"... I'd consider unpacking that as I feel like that's what this story is really about.

Hope this helps.