The Disturbance at Foxwood Court by Gillian St. Kevern

There’s no Royal Society for the Protection of Werewolves.

Taming a stray dog was supposed to occupy Pip while he recovered from illness—not embroil him in a chilling supernatural plot. Nothing in his occult library explains how to care for a juvenile werewolf, but Pip knows this much: he would sooner die than let Julian be recaptured by the sinister Professor Rathbone.
He might have to. Rathbone will let nothing interfere with his experiments. To save Julian, Pip must risk his life, his reputation, and the world he’s built with Cross.