Aw, I feel for you hon. If your little one isn't sleeping that means you aren't sleeping.
First, kudos to you for not ignoring his fears or telling him things aren't scary or he's not afraid.
Second, be careful not to feed his fears. Rearranging his room and catering to his separation anxiety can rob him of the chance to develop coping mechanisms which is an essential part of growth at this age.
A book series I love it the 'Happiest kid on the block' there are separate books for babies, toddlers, children, etc. The happiest toddler on the block has a couple chapters on dealing with separation anxiety, which children will phase in and out of regardless of their situation around ages 7 months, 1, 2, and 3.
The technique that worked best with all 4 of my kiddos involved getting them used to separation with practice. First dedicate about an 30 minutes to playtime with your kiddo - both you and your husband (and the absent dad on webcam too if possible) For the first 5 minutes its all about the kiddo. After 5 minutes, someone says "oh I forgot something, I'll be right back" and walks out of the room for 30 seconds - the other 2 adults keep playing with the kiddo and ignore the fact someone has left. After 30 seconds, the absent person comes back and gives the kiddo a hug regardless of whether your son acted brave or scared. Say things like "see? I said I'd be back and here I am! Thanks for waiting!" then play for a few minutes and its time for another adult to announce that they have to do something and will be right back. Gradually move it up to a little longer each time.
Keep a digital clock in view, Once he's ok with someone being gone a couple minutes then a couple sessions later you can say things like - "I have to go potty, I'll be back in 6 minutes" The other adults can keep him busy while you are gone and can also let him watch the clock so he feels like he has control over when you will be back. Just be sure not to let him tell you when to return or control how long you are gone. Come back when you say you will and not a second sooner or the next time the anxiety will be worse for him.
-------the above works if your son is developing normally and there hasn't been any recent trauma-------
I had to edit myself here. You know your situation - if your kiddo is just 'going through a phase' my above advice will work. I personally haven't slept more than 3 hours a night since I was 4 years old due to a traumatic experience that happened when I was little. I'm cool, can't remember anything that happened to cause it but my brain doesn't like to switch off.
My parents had to take the therapy route with me and eventually stopped turning off my light or tucking me in and instead turned on some friendly kid music, handed me my nintendo controller, and made sure I had enough books and a snack for 3am so they could get some sleep. I'd usually pass out around 4 and be up by 7.
So - if you suspect your kiddo has irrational fears caused from something that really happened, he may be showing signs of ptsd and rather than seeking advice here - you should get him seen by a counselor who specializes in childhood fears.