Until 1906, in Jelgava has not lived people with the surname Redison. But such a name is found elsewhere. You must contact Ministry of Justice's registry office to get the birth record of your wife's father. Perhaps there will be specified, where his father was born. If not, it is necessary to request information about his marriage or dead. Then you know exactly where he came from .
Aleksandra Čaka ielā 38a, Rīgā, LV-1011
dzimts.dep@tm.gov.lv