Are you swaddling him? Neither of my kids would sleep at all if they weren't swaddled. How about white noise? If he's a light sleeper, some white noise will help to drown out other noises and help him sleep longer stretches.
I don't know how old your baby is but you just might have a case of 'crying it out'. My daughter went thru the same thing at about 18 months. As soon as I walked out of her room (or shortly thereafter), she'd start to cry. At some point, I had to say: "Enough!". For my own sanity, I just had to let her cry. The first night, she cried for 45 minutes, the next, 10 minutes, then just a few minutes and that was it. It did the entire family a whole lot of good (including her)...
Sounds like teething + separation anxiety.
My daughter threw sleeping right out the window at 8 months when teething really became an issue. She was up every hour or so whether I was in the room with her or not.
I created a new nighttime routine of putting orajel on her gums right before her night time bottle...then holding her and singing to her while she drank..then just holding her in bed or the rocking chair until she was *fully* asleep. She'd usually make it about 3-4 hours on that routine, but then be back up, and need more oragel ... and more snuggling. I could sometimes get her back to sleep in as little as 10 minutes, but sometimes not. Either way, *I* was now awake :(
My sleep *stayed* broken. We tried attachment parenting up to and including putting her back into bed with us to co-sleep. Epic fail. Nothing we did stopped her from waking and winging about every 3 hours. You just can't safely give a baby enough panadol night after night to stop teething pain, so there's nothing for it but to let them learn to deal with discomfort.
So finally at 12 months I said enough's enough and resorted to the cry it out method. The first night, I kid you not, she wailed like a banshee for no less than 1 hour and 45 minutes with *maybe* a couple 10 minute breaks. I was afraid the neighbors would call the police.
The second night, I fell back into the pattern of soothing her...I left my bed and went to her, managed just barely to avoid picking her up and *holding* her till she went back to sleep, but was still awakened by a befuddled husband who wondered why I'd slept in the chair by her crib side instead of in my own bed.
The third night, I heard her wake to begin her wailing...and I went out and made sure she hadn't dirtied her nappy. Then I laid her down, covered her with her blanket, and left the room. She wailed for about 30 minutes....then slept for almost 5 hours straight.
Last night, she only cried for about 20 minutes around 1am (after being put down at 8:30) and then didn't wake again until 545am...she whimpered loud enough I heard it on the baby monitor...but then apparently rolled over and went back to sleep. She was *awake* when I came into her room at 745am...but she was sitting calmly in her crib playing with some board books and her lovies.
You will have to decide if you wish to try crying it out or attachment parenting.