Ancient Fire — Mark London Williams

The year is 2019, and a secret government agency is forcing Eli Sands's dad to continue with his time-travel experiments, even though Eli's mom has just disappeared in one. Then Eli himself demonstrates an unexpected ability to travel through time. Now he has a ridiculous new code name and a gravely important mission. With the help of new friends -- Clyne, an intelligent dinosaur from an alternate Earth reality, and Thea, a girl scientist from ancient Egypt -- Eli must investigate a deadly disease, search for his mother, and stay alive.