The answers to both are "yes", except that the "if so" bit I can't find reference for. Jewish moneylenders sometimes funded wars, and their lending in general got them better treatment, but not in that cause-and-effect way.

This article talks about wars funded in part by Jewish lending. They include the American Revolutionary war, the Franco-Prussian War, various French wars under Louis XIV, the Hundred Years war, and the Napoleonic wars.

And lending sometimes got Jews help. The Jewish migration to Poland in the 11th-14th century was due in large part to the favorable treatment of Jews by the government there, which was done to strengthen the economy by bringing in capital.

However, I can't find reference to a cause-and-effect relationship. It certainly didn't help the Jews in Spain. It seems to have had the opposite effect, actually. Nobles or monarchs would stir up resentment towards the Jews, leading to them fleeing, which would free them of their substantial debts to Jewish moneylenders.