You can try, but there's nothing you can really do.
Law states that if no will is written and signed with witnesses that all property is thereby held and given to the wife.
If his will was written completely and signed, no big deal as you know, but seeing as it's not - there's not much you can do.
Irregardless as to how much we tell you on here, NOTHING is going to work out better than sitting down for a solid consultation with a lawyer. Hell if you have to, get in touch with one of the lawyers that only gets payed if you win the lawsuit - get their opinions, find out.