I’m happy to hear the nettle wraps have been helping.
If you are considering making an oil form nettle I would do it with the dried plant but it is not going to give you quite the same results as using fresh nettle directly on the skin (e.g. that sting that brings fresh blood to the area will no longer be active).
For this situation, you could also use a comfrey oil, st.john’s wort (both as an oil externally and tincture or tea internally-if he is not on any contraindicated medication). Otherwise internally, yes, keep up with the nettle, adding milk thistle would help and you could use dandelion (root and leaf) and some turmeric.
I hope this helps out a bit and if you have any further questions, don’t hesitate to ask!