Can my father stop my little brother from seeing me, I am 36 and he is 13. We are very close but our father is a very bitter man and is trying to punish me by preventing access to my wee brother, can he keep us apart?

Depends on what country you are in.

Most likely yes. At least until he is 18.

Can you try making amends with your father?

If you are in the US, yes, there is no "rights" to see brother. Your brothers guardian or parent has full right to stop you from seeing him. Where is your mother at ?