Honestly, I would pick a bit easier topic, moreover, if you are a newbie in this field.
haven't we all been newbies in this field not so long ago
if he is willing to study the material and is smart
he will become an expert sooner than you think,cryptocurrencies is not something extra hard to grasp
but then there might be a thesis that sums up all the information about legal aspects of crypta in one place
win win in my books,so don't discourage the man or throw him your one line definitions