He became seriously ill on the sled journey and despite an improvement which allowed them to enjoy Christmas he soon became very seriously ill again Crelle was told and he redoubled his efforts to obtain an appointment for Abel in Berlin

What is the correctly punctuated version of this sentence?
He became seriously ill on the sled journey and despite an improvement which allowed them to enjoy Christmas, he soon became very seriously ill again. Crelle was told and he redoubled his efforts to obtain an appointment for Abel in Berlin.