I think from here on out it's up to the family. I know right now several actors have been getting digitally scanned from head-to-toe, and recording their voice, so in the future if there is a part they are too old to play, or they have passed on, their family can decide to allow them to be used in movies, games etc.
If his family feels like it would do him honor to be in the next in a limited way, most fans would support their decision. It's nobody's choice but theirs.
Not sure how they would do it though.