All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If the deceased did not leave any other heirs except his son, then his entire inheritance is for him by Ta’seeb (by virtue of having a paternal relation with the deceased and not having an allotted share).
It should be noted that the matter of inheritance is very complex an issue, so a mere Fatwa which is an answer issued according to the question is not enough. Rather, the matter should be taken to an Islamic court to look into the case, or it should be presented orally (in person) to the scholars in case there are no Islamic courts. It might be that there is an heir who would not be known except after investigation, and there might also be a will, debts, or other dues that are not known to the heirs. It is known that these rights come in priority over the right of the heirs. Therefore, the inheritance should not be divided without resorting to an Islamic court, if any, in order to fulfill the interests of the dead and the live people.
Allaah Knows best.