Without knowing its condition, there’s no place to start. If he wants to sell or insure it, he should have it appraised. He can check the auction sites for comps. I am not at all familiar with that particular model. Enfields are more troublesome than SMLEs, if such a thing is possible.
Is it an original or a reproduction? If it's a reproduction, where was it made? Is it 100% complete? And then...what's the condition inside and outside.
When ALL those are known, it's possible to give you an answer.
Until they are answered, your question is parallel to asking;
