Looking for Per Persen and Petter Bertel Persen

My great grandfather had two brothers who emmigrated from Trysil, Norway to the US. I am looking for any living relatives of Per Persen (born 06/12/1876) and Petter Bertil Persen (born 04/11/1880). I have found one of their sister, Desema Peterson, but unfortunately she passed away in 1996 in Spokane, Washington. Thank you:-) Therese