Why does Mr. Johnson stay at home while the rest of his family goes to Henrick's?

Mr. Johansen stays at home when the family moves Annemarie and Ellen to Uncle Henrik's home on the coast. Mr. Johansen stays at home in hopes that the Germans will not be as suspicious of the family moving if they do not all move together in a unit. The Nazi soldiers are already very suspicious of the family and the Johansens are hoping that breaking up the family will throw the Nazis off their trail long enough to move the girls into a less immediately dangerous place. Mr. Johansen is not thrilled at staying behind while his family makes a dangerous move across the countryside, but he understands that the decision may be their best hope at keeping Ellen alive. Mr. Johansen uses coded language to ask Uncle Henrik if it is safe to bring the girls to his home by asking if "the weather is good for fishing," and upon receiving an affirmative response, tells Uncle Henrik that he will be sending along a "carton of cigarettes," meaning the girls, to his home.

After the Germans come looking for the Rosens, it's clear that the Johansens are in serious danger from the authorities. Mrs. Johansen managed to convince the Germans that the little dark-haired girl is actually Lise, not Ellen. Although the Germans leave empty-handed, everyone knows it's just a matter of time before they return. Mr. and Mrs. Johansen decide that the best course of action would be to take Ellen and Annemarie to stay with Uncle Henrik, a fisherman who lives by the coast. Mrs. Johansen thinks it would be better if she went with the girls while her husband remains at home. At first, Mr. Johansen's none too enthusiastic about the plan, but he eventually agrees, realizing that it would potentially attract too much suspicion if the whole family left together.