The pipe not use "tee" to print on the screen for specific function

Shell Programming and Scripting
1

I have code fragment like

        {
    aa
    bb
    cc
        } > $LOG

aa bb cc, all call function "ff", I want "ff" to print on the screen,but others do not print on the scree, is there a method? I can't use "tee", becasue tee I meet the write "error"

ff()
{
    echo "hello"
}
2 
ff()
{
    echo "hello" > /dev/tty
}
3

Traditionally, those sort of messages go to standard error, file descriptor 2.

echo "hello" >&2