15 month old sleep issues

[Chantal1310]

My 15 month old used to sleep from 7p.m to 7a.m. Until about a month ago. Some nights he goes to sleep in his cot, then wakes up screaming in the middle of the night and can't wait to get out of the room; he reaches for the door. But the screaming continues. He reaches towards the cupboards, the fridge, anything but doesn't seem to know what he wants. Last night though, we put him in his cot and he didn't even go to sleep. He screamed solidly for about 2 hours and was inconsolable. Trouble is, we've been letting him sleep in our bed during these episodes and I'm worried that he's getting a bit too used to it. He's had some sort of virus and maybe a cold and is teething and has been sent home from nursery with a temperature so has had to have a couple of Covid tests so there's a lot going on for him poor little thing. I'm just wondering if anyone knows whether at that age they have the intelligence to think "if I scream, I get let out of my room and can go sleep with Mummy and Daddy". I don't want to get into a habit of him sleeping with us, and am trying to be patient at a tough time for him. Part of me wants the comfort for all of us of him being in our bed so he's not upset, but part of me wants our bed back! It's really distressing for all of us. Any words of wisdom?