The closest that you’ll find to the Kaddish in terms of its text, at least according to my very limited internet research just now, is probably the Sanctus, which in the Syriac tradition is known as the Qadish (not to be confused with the Qadishat, which Thomas48 posted; that’s a different prayer). Here is the Qadish as recited in the Syriac Orthodox tradition, though I don’t know if it’s said at funerals or not:
Qadish. According to wiki (I know, bad source; I’m tired and others might do actual research if they wish), this prayer is rooted in Isaiah and the first part of its text matches the congregation’s chant during the kedushah (part of the Amidah, prayed during the Jewish liturgy).