If the $2100 includes the $400 junk fee then it is different.

Dad owes $400 plus one third of the remaining move out fee of $1700 which is $567. So dad owes $967 total.

The remainder of the move out fee which you and H are responsible for is $1133. Subtracting the $500 deposit leaves $633 that you need to pay.

I think that should be correct based on the new info you provided.