Is it safe if I post the details here? If I mention the sum and the Receiving address, would somebody be able to help me check and interpret?
Yeah, it's fine. It's a public data anyway. Either give the tx id or give the address. You can do it yourself via Blockchair or other block explorers.
If he did send the money, there's no need for a screenshot or anything. The tx id would be more than enough to check the transaction yourself. Unless the TX was dropped from the mempool and not confirmed.