Sorry to ask do you check his profile before wanting to deal with him, he has already a tag as 'likely to be a scammer' which is called to be careful of such user before you could get scammed. If possibly he should go for the transaction first before you sending to him, if at all you really want to deal with him.
Of course I am not sending first to someone who has nothing to lose. And I am aware of the possibility to send fake tokens or a wrong chain. I've also seen people who try to send private keys or accounts on shady websites.
From your request to get the amount in crypto is simply means with the current price of btc today 27/10/2022, 5:53am at $20817 Is therefore
$100/$20817 = ~0.004804BTC please also know that this value may likely change if the bitcoin price goes high or low.
My point was to set a hard amount instead of something that fluctuates.