My 2.5 yr old son has stopped sleeping in his room at night and the lack of sleep is affecting his behaviour. Desperate for help :(

About 2 months ago, our youngest Logan started to refuse to go to sleep in his room. He'd be fine falling asleep anywhere but his room. We tried laying in his bed with him, reading to him etc. It worked a couple times, but for the most part he just screams at bedtime. So, we just let him 'crash' anywhere, and put him to bed. He does not sleep the night. For weeks he'd wake up between 2am-2:30am. He would scream and scream till we go get him. He can scream upwards of 2 hours ... he will throw his toys, bang on his walls and door. He recently learned to take off his door knob cover and comes inti our room. In the last few weeks he is waking earlier and earlier .... some nights as early as 11pm. When he wakes, its just a matter if time till he ends up in our bed. We have waited till he is asleep again and try to put him back in his bed but he wakes up and screams again. We have tired going into his room when he wakes at night and sitting/laying with him, but he tries to leave his room and screams non stop till we let him out of his room. He loves his room. He will go into it to play during the day by himself. There are tennants in the basement, who we know have woken him up many times. They slam their door, and the vent in his room is connected to one of the bedrooms in the basement. We have stayed up some nights till he wakes to see if there is any noise waking him, and we dont hear any. We dont know why he wakes up. It's been 2 months of hell. I am exhausted. I've noticed a negative change in his behaviour lately. He seems very tired during the day. He's moody. He's basically unpleasnt. We are at a loss for what to do. I dont know how to keep him in his room. I dont know how to get him to sleep the night. I just dont know!!! I looked into a Sleep Doula. They are about $250/night .... not a possibility. The tennants in the basement keep complaining about his screaming at night, and he's waking up our other kids. Neither of which did this, or anything close. I"ve talked to his Dr, friends, family, no one has any advice. I do not like him being in our bed. Our other kids didnt sleep with us. I'm not the 'family bed' type. I wake every time he moves in our bed. I get very little sleep. My husband sleeps like the dead. I'm drained. I am desperate for help. Any suggestions are welcome. Selling him is NOT an option though!!