Editing a pulp anthology

I've been compiling an anthology of old pulp fiction stories by writers from the Turku region. The book will be published by Pelipeitto next March and it will also feature a bunch of new writers, such as Boris Hurtta, Markku Soikkeli and Sami Myllymäki, and perhaps Kirsti Ellilä. There are also some old stories by such present-day veterans as Pirkko Arhippa and Totti Karpela.

But there will also be four or five stories from the thirties and fourties (well, at least three). I've tried to gather information about the writers' heirs. It seemed to be very difficult at first, when I tried to go the legal route, through magistrates and such, but then it clicked: I just googled. Well, it wasn't as simple as that, but it proved to be more fruitous than I first thought. I've managed to secure the rights for a story by Aake Jermo and will be phoning for some others next week. There was just one writer about which I'm not so sure what to do: there are three heirs, two daughters and a son. One daughter is suffering from a bad case of dementia and the other daughter and the son don't speak to each other. I talked to the son and he said everything's okay, but you'll have to ask the other daughter first. "But don't say anything about me or it backfires. She's a nuisance, totally unpredictable."

I didn't phone the other daughter, as I wanted to hear what the publisher had to say about this. Can we go only on the base of the son's okay? I'd really like to print a story by the said writer and wouldn't want to tackle with the bitter and angry heirs. The son said that his father would've been delighted to hear someone wants to reprint him, but it seems that not everyone thinks so.