theres likely other quests locking him up likely relating to cecily or if thats not the case your weak may be too high to talk to him.(not gaurenteed to be a thing but i am making this recommendation based on other things)
https://drive.google.com/file/d/1uleQJo-Fvy7YhFts6Q2Ybc3l2j4MDrE1/view?usp=drive...
also, after completing milo's first quest and talking to him again after a few days, he still gives me the same first quest (killing adam) even though i've already done it.