Sforno on Numbers 27:3/ספורנו על במדבר כ״ז:ג׳

1והוא לא היה, he was not a member of the rebellious people who had made common cause with Korach. Those people had been banished by Moses, i.e. disinherited by him, deprived not only of potential property but even of all their actual belongings, as we have been told in Numbers 16,26. The words כל הרכוש in verse 32 of that chapter make clear that they had forfeited all claims to anything.

2כי בחטאו מת, he died on account his personal sin, something that did not involve the claims of his heirs to his estate. [The daughters by saying this did not mean to malign their father; rather they meant to say that their father had completely atoned for his sin by his premature judicial execution. Gottlieb]