Why was Dad trying to reach Jake?

It was stupid. Just like the rest of the film. At one point their truck breaks down. The guy says "where are we" and the other guy says "just north of philadelphia". So in the middle of the worst type of storm they walk to new york in a matter of days from beyond philadelphia.

Because hes his father, because he said he would come for him. You would do anything for your children thats why. Yes stupid but he was keeping his promise.

Also Jake isnt his name. Since you used the word dad and not Dennis you would call him Sam.

It was so stupid. And he barks at them "We're walking from here. Get your snow shoes."