It is not possible to offer any idea of the cost of dealing with this issue. It is too vague. There may be all sorts of hidden issues.
It sounds as if your brother is going to deal with the Grant of Administration, you will all disclaim your interest in your fathers estate, there may be issues with your mother's estate also and then you all want to vest the property into your brothers name.
You really need to talk to a good local solicitor who will advise you on what steps to take and the approx. cost of so doing having elicited all relevant information from you.
mf