Wouldn’t it be a good idea to at least ask? Professor E-V might not have ideas, but he would have contacts at Oxford where he/Harry could find other ideas. The downside is that, by involving the non magical world, his family and those contacts will become bigger targets. And I suspect Harry would be loathe to expose them with an unknown enemy with largely unknown capabilities.
Wouldn’t it be a good idea to at least ask? Professor E-V might not have ideas, but he would have contacts at Oxford where he/Harry could find other ideas. The downside is that, by involving the non magical world, his family and those contacts will become bigger targets. And I suspect Harry would be loathe to expose them with an unknown enemy with largely unknown capabilities.