How does the Family Code define “family”?

The family, being the foundation of the nation, is a basic social institution which public policy cherishes and protects. Consequently, family relations are governed by law and no custom, practice or agreement destructive of the family shall be recognized or given effect. (Art. 149, Family Code)

What relationships are included under the term “family relations”?

Family relations include those: 

(1) Between husband and wife; 

(2) Between parents and children; 

(3) Among other ascendants and descendants; and

(4) Among brothers and sisters, whether of the full or half-blood. (Art. 150)

What is the requirement if there are suits between members of the same family? What is the reason behind the requirement?

If suit is between members of the same family, there must be prior earnest efforts toward a compromise; otherwise, the came must be dismissed. 

"No suit between members of the same family shall prosper unless it should appear from the verified complaint or petition that earnest efforts toward a compromise have been made, but that the same have failed. If it is shown that no such efforts were in fact made, the same case must be dismissed. This rule shall not apply to cases which may not be the subject of compromise under the Civil Code." (Art. 151, FC)

The reason for the law is that a lawsuit between family members generates deeper bitterness than one between strangers.  Hence, it is necessary that every effort should be made towards a compromise before a litigation is allowed to breed hate and passion in the family. (Esquivas vs. CA, G.R. No. 119714, May 29, 1997)

What does "members of the same family mean"? Is there a need for efforts to compromise if there is a stranger to the suit between members of the same family?

The phrase "members of the same family"in Art. 151 of the Family Code must be understood as referring to the relations enumerated in Art. 150 of the Family Code under which "family relations" include only those (a) between husband and wife, (b) between parent and child, (c) among other ascendants and their descendants, and (d) among brothers and sisters. Hence, if there is a stranger to the suit, such as a brother-in-law or a sister-in-law, compliance with Article 151 is not jurisdictional for the maintenance of the action. 

"Efforts to compromise" are not a jurisdictional prerequisite for the maintenance of an action whenever a stranger to the family is a party thereto, whether as necessary or indispensable one.  An alien to the family may not be willing to suffer the inconvenience of, much less relish, the delay and the complications that wranglings between and among relatives more often than not entail.  Besides, it is neither practical nor fair that the rights of a family be made to depend on a stranger who just happens to have innocently acquired some interest in a property by virtue of his affinity to the parties. ((Esquivas vs. CA, G.R. No. 119714, May 29, 1997 citing Magbenta vs. Gonong, No. L-44903, 22 April 1977, 76 SCRA 511)

Enumerate the cases which may not be subject of compromise

No compromise upon the following questions shall be valid:

(1) The civil status of a person;

(2) The validity of a marriage or legal separation;

(3) Any ground for legal separation;

(4) Future support;

(5) The jurisdiction of courts;

(6) Future legitime. (Art. 2035, Civil Code)