Eliza remained in close contact with William and Delphy Costin throughout her life .
Delphy and her children were manumitted by Thomas Law and Eliza P. Custis Law in 1807 .
Eliza P. Custis Law remained in close contact with William and Delphy   throughout Eliza P. Custis Law 's life .
Delphy and her children were manumitted by Thomas Law and Eliza P. Custis Law in 1807 .