In case he filed your case, he may need to provide the following:
1. Courier tracking number
2. Receipt Number (In case you got picked in lottery), which also specifies the cost and petitioner on it.
3. If he applied in 2017 and you were not picked in lottery, he may need to provide with the rejection notice from USCIS.
So, my question to you is which year he applied your H1B?