This is one of the earliest arguments for copyright protection: "Look at the poor grandchild of [famous author], begging in the streets. If we had attached exclusionary rights to his works, she would benefit from his works!"
I'm not saying it's a good argument (it's sentimental, for starters, not that OPs is much different - "proprietors" didn't invent IP law, and Disney is apparently giving its pound of flesh back to the powers that helped it game the system), but I'm pretty sure the same one was used in defenses of generative work and, notably, NFTs - "this will help the poor artist, who would otherwise have no market." Rogers v Koons put paid to that argument (indirectly), and I'm hoping the current class actions succeed, your brother notwithstanding.
I'm not saying it's a good argument (it's sentimental, for starters, not that OPs is much different - "proprietors" didn't invent IP law, and Disney is apparently giving its pound of flesh back to the powers that helped it game the system), but I'm pretty sure the same one was used in defenses of generative work and, notably, NFTs - "this will help the poor artist, who would otherwise have no market." Rogers v Koons put paid to that argument (indirectly), and I'm hoping the current class actions succeed, your brother notwithstanding.