I did some research on this, because the first thing that came to mind was "a conflict of interests". But you're not talking about "interests", you're talking about emotions and feelings (sentimentos).
So, we're talking about something in conflict - conflicting emotions, conflicting feelings. If you have "conflicting feelings" you are feeling both positive and negative feelings. If you feel both good and bad about something, your feelings are mixed. You have "mixed feelings" about something, or you are ambivalent towards it. You feel ambivalence towards something.
Here are some options for translation:
"Ela está frequentando seções de psicoterapia para lidar com um conflito de sentimentos que a invadiu depois da morte do filho dela."
"She's been having psychotherapy sessions (She's been seeing a psychotherapist) in order to deal with the...
...'ambivalence' that has afflicted her since the death of her daughter."
...'conflicting feelings' she's been having since the death of her daughter."
...'conflicting emotions' she's been feeling since the death of her daughter."
...'mixed feelings' she's been having since the death of her daughter." (embora você possa usar "mixed feelings" aqui, você pode usar a expressão para falar da sua opinião de alguém; você não gostou nem desgostou de alguém - you have mixed feelings about them)
This was a tough one!
Hope it helps,