-p is not interactive password input option for sudo command.
There is no such feature or switch.
Please correct the steps for better understanding, you are :
1. sshing to box hosting Oracle database as some generic user.
2. You wish to change the user to oracle user (the user under which the database is ran).
3. Source a file, after which you issue unlock of oracle database account.
If i'm not mistaken, a SYSTEM user should have required privilege to UNLOCK account, and you should be able to connect to database in standard way (sqlplus, toad etc.) and SYSTEM user ?
Why do you require ssh and sudo to do this operation ?
Why not use a DBA_DIRECTORIES or EXTERNAL TABLE in which a sshed user will write a simple text file and oracle will process via internal scheduler and/or procedure.
Use the database software you are paying gold for, you are over complicating it
Hope that helps
Regards
Peasant.