For the destruction of his dimension he is brought into the theraprism. He is a bit crazy still and the theory doesn’t seem to be working but hey he likes the days he gets to do art!
Always drawing the muse that cannot physically leave him. They tried to take him- but for fords wellbeing they can’t!

After that ford feels absolutely betrayed. He gathers himself more power out in the multiverses and comes back with a set idea to destroy the world that betrayed him so badly,he does,but Stanley and fiddleford end up escaping into the multiverse(more on that later)ford is very unstable at this point

Adding more here!!
Ford ends up setting the portal up. In his delusional state he had contacted stanley(he does not remember this)
Stanley shows up and sees how his brother has become. He ends up getting into a fight with him that leads to ford getting pushed into the portal