can the government take your property if you have been convicted of a crime

The answer to whether the government can take the assets of a person who has been convicted of a crime depends on various factors. If the person was subject to a fine, or to an order requiring him to pay restitution, then yes, the government can likely take any assets he receives, including inherited ones. It may be possible for your father to protect the property he wants to leave to your brother by putting it into a trust for your brother, instead of leaving it to him outright. Your father will need to consult an experienced estate planning attorney in the state where he lives to see what his options may be. The attorney will need a lot of information about the crime, the conviction, and the punishment, as well as your father's situation in general, so it's not the sort of answer that can easily be given in a forum like this. It's also not a do-it-yourself project, so you dad should get some professional help.