First I must ask why you want to crate him at night? Is he still potty training or destructive over night? If so theres definitely reason to keep working on it. If not maybe just allow him to sleep on a bed next to yours at night. Many people crate their dogs at night which is perfectly fine, but when dogs (especially rescue dogs) have anxiety about being in their crate its sometimes more harmful to make them be in there when it makes them so upset. If he sleeps soundly next to your bed all night and keeps out of trouble I think that is a better option then the crate.
Another point I'd like to make is that when crate training you need to make their crate as enjoyable as possible. Do whatever you can to make them want to go in there freely. A part of making this crate their safe place is putting it in a safe place for them, which is a place where you happen to be or to spend time. Unless you're spending a good deal of time in your walk in closet, that isn't a good place for the kennel. It may only be 10 feet from your bed but your dog will know when it's being kept in a closet (not trying to make you feel bad about it but make you see that dogs can pick up on being someplace that isn't ideal).
Another point I'd like to make is that when crate training you need to make their crate as enjoyable as possible. Do whatever you can to make them want to go in there freely. A part of making this crate their safe place is putting it in a safe place for them, which is a place where you happen to be or to spend time. Unless you're spending a good deal of time in your walk in closet, that isn't a good place for the kennel. It may only be 10 feet from your bed but your dog will know when it's being kept in a closet (not trying to make you feel bad about it but make you see that dogs can pick up on being someplace that isn't ideal).