You don't need to grant
SYSDBA privileges, and shouldn't unless really necessary. You should follow the principle of least privilege. From Oracle's security guidelines:
Do not provide database users or roles more privileges than are
necessary. (If possible, grant privileges to roles, not users.) In
other words, the principle of least privilege is that users be given
only those privileges that are actually required to efficiently
perform their jobs.
You just need to grant with admin option:
grant references on <schema>.<table> to <user> with admin option;
<user> can then grant references on to others, but can't pass on the admin option.