Urgent help needed for my dog

We've been camping for a week in Gippsland, Victoria together with a lot of mosquitos... My 10 years old rottweiler got sick, he lost almost 10kg in 14 days, running eyes, constipated and vomiting after meals. I tooked him to the Vet, blood tests showed severe red cells shortage, but major organs looked OK. Ultrasound examination revealed tumors in and around his spleen. The Vet advised me that it is not much we can do to save him. The family has decided to take him home (he is very much loved and part of the family, my 6 years old learned walking by holding him, etc.). In the last 2 days he gained strength, is allert, eats small quantities without womiting, - but he is constipated for over a week now.
I have a distinct feeling that the possible spleen cancer just came up because of the tests, but right now there is something else.
Any suggestions are welcommed, thanks. Tweet