His life was the same as his main timeline counterpart up until the time when the Androids came. During the time Future Trunks was fighting the androids, he was hiding and living in a submarine near Kame House with Future Master Roshi, Future Oolong and Future Puar.
"Future" Trunks Saga
Main article: "Future" Trunks SagaWhen Fusion Zamasu used his Lightning of Absolution in his battle against Goku and Vegeta, the impact is felt across the earth. A hurricane is caused and Future Turtle is seen holding onto the roof of Kame House.
Whenever Future Trunks is fighting Zamasu after Vegito defused back into Goku and Vegeta, all living beings on the Earth give their energy to Trunks. Turtle is seen glowing as he gives his energy to Trunks. He was later killed along with the remaining humans of the future timeline when the Bodiless form of Zamasu used Chou Makouhou Barrage to attack Earth.
Second Future Timeline
While Future Turtle died during Fusion Zamasu's final attack to wipe everyone out, he still exists in the second future timeline created by Whis' alterations.