Use the IRAC Formula to cover the rule of law and apply it to the situation, this relates to fiduciary duties of an attorney

Eugene H. Emmick hired L.S. Hamm, an attorney, to draft his will.  The will named Robert Lucas and others (Lucas) as beneficiaries.  When Emmick died, it was discovered that the will was improperly drafted, violated state law, and was therefore ineffective.  Emmick’s estate was transferred pursuant to the state’s intestate laws.  Lucas did not receive the $75,000 he would have otherwise received had the will been valid.  Lucas sued Hamm for breach of the Emmick-Hamm contract to recover what he would have received under the will.  Who wins?
What matters is fiduciary duties of an attorney.
[Lucas v. Hamm, 364 P.2d 685, 56 Cal 2d 583, 15 Cal. Rptr. 821 (CA 1961)]


Please describe what the Issue, Rule, Application and what the conclusion would be.