Is it permissible to offer condolences to the family of one who died in Syria, claiming it was for jihad, or is that not permissible on the grounds that it is considered terrorism?

Consoling and commiserating with the relatives of the deceased is a right for the living, to comfort them, not for the deceased. It is permissible to console a living Muslim in their affliction, even if they are disobedient or an innovator. Indeed, it is legislated to console a dhimmi, according to the preponderant opinion of the scholars. It must be noted that labeling someone as a terrorist requires a precise legal (Shar'i) definition to control it and clarify its ruling, as some have expanded this concept to include those who defend their basic rights.