Okay, here’s that census from Mandal that was missing in my post above.
1865 in Mandal Thomas Thomassen 45 born in Mandal Karen Tomine Thomassen 43 born in Mandal Nicoline Mathilde Thomassen 12 born in Mandal Thomas Eid Thomassen 10 son, born in Mandal Torje Marie Thomassen 10 daughter, born in Mandal Knud Rudolph Fischer Thomassen 5, born in Mandal Nicolay Marcelius Thomassen 2 born in Mandal Maren Marie Thomassen 2 born in Mandal Oline Thomassen 58 unmarried Adolph Mathinius Thomassen 31 unmarried, SEAMAN Ane Elesabet Nielsen 23, unmarried, servant
I believe your Thomas Thompson had a father Thomas Thompson and mother Anne Maloney/Mahoney per death cert (hard to read). But I distrusted that name as being his mother, since his wife’s mother is almost the same name (makes it seem like a mistake). Are we going on that hypothesis - that Anne Maloney/Mahoney is not necessarily his mother?
If one thinks the name "Anne" could be right, then there is only one mother ANNE in the short list of five boys. BUT I think that if the name is wrong, it's wrong - there's no reason his mother would be Anne.