Even if Donald let's Della see the boys after the trial, he is personally done with her. Plus for a while he can't trust her with the boys alone till their teenagers. He has this paranoid fear she's going to just run off and take them on a whim or when she's having a bad day. For the first few weeks/a month neither of the boys wanted to see her.
Can you even imagine the strained relationship between Della and teenagers HD&L ? I feel like Huey and Dewey would still goes the extra mill to being close to her even if they will never forget how she had acted in the past but Louie is done with her and went no contact and Della probably blaming Donald for that and that open a new can of worms but anyway
Donald fear of someone taking the boys away from him is legit like those are his boys, his and his alone and now he even has approval of the court so yeah.
I'm wondering where Webby fits in all that actually and nobody can take the 'Webby sees Donald as her uncle and the triplet as friends/siblings' headcanon from me and truly want to see where she could fit in all of that