He has no feelings. He saw Madara with his DNA and didn't say anything. I guess he doesn't really care, I mean he's dead haha.
Hashirama didn't seem to care that Orochimaru had his cells; he even laughed at Oro using them to bind Tobirama.
how do you think he'd react to everyone craving his DNA?
this is just like what happened with Henrietta Lacks, im curious to see your responses
Hashi is a nice guy he wouldn't care.