It looks to me that you got the sentence a bit wrong - they way it is, it isn't correct:
he spoke good things about his (girl)friends-----הוא דיבר טובות על החברות שלו
if you want to use the verb told - he told me good things about his girlfriends it would be:
הוא סיפר לי דברים טובים על החברות שלו
and to say: he told me about his good girlfriends, it would be:
הוא סיפר לי על החברות הטובות שלו