If you think that undue influence of any sort was brough to bear upon your mother either in the matter of transferring the house to your brother, or in the matter of preparing the will, or if you think the transfer was done very shortly before her death, at a time when she knew she was dying, then you might want to consult a solicitor. However, bottom line is that as long as your mother knew what she was doing and was happy to do it, the house was hers to give away. Any competent solicitor would be particularly careful to ensure that someone in your mother's position definitely wanted to go ahead with such a transfer. Almost all solicitors would insist that your mother have independent legal advice. Despite this, there are always a couple of cases each year where such transfers get overturned, so it is no harm to mention it.