。
She wasn't taken into account at all in his will.
Literal
She [topic-は] his [genitive-の] will [in-では] anything [also-も] wasn't-considered.
何も~なかった ('nothing at all') is the standard 'nothing' construction with a negative predicate. The では combines で (location/scope marker) + は (contrastive topic), focusing on 'in (his will) specifically.' 考慮される ('be considered') is the passive of 考慮する. The construction is impersonal — passive without an explicit agent, suggesting the will was a closed document that simply didn't include her.