Hi there,
Beardies often dig because they want to find somewhere safe and enclosed to sleep.
It sounds like he would definatly benefit from a hide.
Dexter used to dig at night untill I made her a hide.
I made a temperary 'makeshift' hide whilst I try (and fail a few times) to build her one from wood. All you need to do is get a shoebox and cut a small door into it. Inside you can add a section of towel/flannel if you like. I did because my dragon loves soft surfaces and dragons do like to feel surrounded and safe whislt they sleep.
As you can see it takes 5 minutes to make!
Build her one and pop her inside/half inside on the first night as she might be too much of a fraidy cat to explore it herself.
Dex took to hers like an alcoholic to a good scotch.
She also stopped digging and seems happier.
Another question would be, Is your beardie female?
If so how old is she and has she been in contact with a male?