The first surrogate-mother trial was recorded in the bible. Sarah and abraham used haggar and she bore ishmal. They did this because they were impatient with god's promise to abraham. Approx. 8 to 10 yrs later, sarah bore isaac, and god's promise was fulfuilled.
However, read the rest of the story and you will see that things did not work out very well. Needless to say, the scuffel continues today between the decendants of abraham. (the middle east....The sons of abraham).
your intentions are admirable, but just remember that "hell is paved with good intentions." just be sure that god should factor into your decision.....Maybe an out right adoption of one of the thousands of children in this country, would be an even more loving answer for your relative. After all, any pregnency hold a certain amount of risk to the mother and child.
If you proceed on this course, be sure that all parties involved are ready to accept any and all consequence's. May god bless you in your decision.