This is quite a wrong question, XEM for example is at 0.22 cents but it is much harder for it to double up than Counterparty which is at $10 now. Do not look at the coin price, look at the market cap.
In that case you should better tell him that you think that XEM isn´t undervaluated,to tell the truth yes,it seems overvalued,with respect to counterparty I do not know much about this but after you mentioned this
there is something that caught my attention regarding this,as far as I could see it was created and distributed by destroying bitcoins in a process known as “proof-of-burn”, is it true?,although I do not know the exact number of coins burnt I find it quite questionable.
Edit: So that 0.0062238095238095% of total supply of BTC were burned by them,at current prices something like 4.18M USD.