A and B were friends. From 2007-2010, A worked for B and helped build B's business until the end of 2010 when A became too sick to work and incurred significant medical expenses. In 2011, B writes to A, "For all you have done for me over the years, I'll pay you $1m to cover your medical expenses." B does not pay A the $1m. A dies in 2012 and A's estate sues B to recover the $1m. Can the estate recover? Why or why not? Respond using IRAC.