Although The Unfinished Swan shows Milton's fate, me and my friend have two theories on what happened to him:
Milton ran away and managed to escape the curse
Milton is living inside the walls
Proof for my first theory:
At the beginning of the game, Edith mentions someone put a chain fence, but it looked like she wasn't the first to hop it.
Proof for my second theory:
The house is in perfect shape, despite being abandoned for 6 years.
Some of the lights still work.
Throughout the game, I hear this noise, sounding like laughing or crying.
Well, that's it! If you have any other theories about Milton, I would be happy to know in the comments! If you have anymore proof about my theories, I would be happy to let me know in the comments.