Stories very often leave some details to the imagination. We are only told of the horrible storm and of how Ludwig was barking frantically a distance away. Ludwig was running around in circles, half-blinded by the forceful rains and wanting to be rescued by Jan. Jan, for the first time, could not give in to the love and devotion he has always felt for his pets. It was either he helped Ruth to save Edek or he went after Ludwig. He chose the former. So, it is up to you to surmise what may have happened to Lugwig. My guess is, he did not make it through the storm. Then again, maybe he did as the rain had already began to ease and we are told that Ludwig made a sudden bolt inland.
As for the parents, the father was a headmaster so although we are not told his age, we can assume that he is somewhere in his thirties to early forties. Again, you need to rely on your creative imagination. If the parents have three children and the oldest being 13 yr old Ruth, what do you think the ages of their parents might be? Being told everything takes the fun out of the story, don't you think?
If you'll read the book, you'll know clearly what happens to Ludwig. I'll give you a hint by telling you that Jan has to make a choice between saving Ludwig and helping to save Edek. Ultimately, he makes the right, though painful, choice.
As for the parents, I'm not sure their exact ages are given, but since their oldest child is a teenager, they have to be at least in their thirties.
jan abondons ludwig for the sake of saving edek. the parents age however, is not given
During the Storm in chapter 27, Jan had an terrible decision to make, it was either the family(Ruth,Edek and Bronia) or the dog(Ludwig); but with a great effort of will Jan shed Ludwig from his mind and turned to his family. In that moment of decision Jan began to grow up.
The novel did'nt give specific ages of the parents, but because the eldest child is a teenager, we can say that the parents are in their thirties.
The dog, Lugwig was lost in a storm. Jan was asked to choose to find the dog or to follow the family. Jan decided to follow the family and left the dog.
I think the parents were above 40 something.