>>5437571If I were to try and goad somebody like Future Gohan into working for me against the Time Patrol, I'd just give it to him straight.
I'd show him exactly what the future has in store for him if he passes up the opportunity to work with me and leverage my resources.
A slow death, beaten and broken because he just wasn't strong enough.
I'd cap that off by telling him that the Time Patrol would do everything in their power to make it happen. Which is, again, the truth.
At that point, it's the choice between dying and leaving Trunks to try and fill the shoes even he couldn't fit into, or take his fate into his own hands and give what's left of Humanity a fighting chance.
Past that, it wouldn't be hard to get him to see Xeno Trunks as being manipulated by Chronoa, which would definitely piss him off enough to stay.
Fighting Xeno Goku might prove a challenge, but even then it wouldn't be hard to spin the same yarn. Gohan knows how naive his father could be after all.