All of us feel obligated to assist our family members from time to time. Our immediate and extended family often know no bounds when it comes to asking for help. I am fully aware of the Biblical position on this but the heart often has a firm grip on us when it comes to helping out.
So when is enough?
How do you determine when enough, is enough?
Here is what I have used as a guide. It has served well in our situations, but I don't recommend someone to use it without the marriage partner's agreement.
First, as the husband, we did not carry over traditions and my family relationships into the marriage. We (my wife and I) established our own, and having "left the mother and father" we also established our own matters of finances, pleasures, standards, ... Not that some were not adopted from my own home life before marriage, but only upon full agreement with my life partner.
Second, as pertains to the wife, she is not required to leave mother and father, but to be under the authority (covering) of the husband as it is transferred from the father. So, more often, sisters, brothers, mother, father, would be more involved in the home. This is not untypical for the woman, as part of their being is to be more social toward her family and friendships.
So when it comes to helps.
If it involved my father, mother, siblings and IF it did not interfere with the family financially, vacations, standards, ... then we would assist if needed.
If it involved my wife's father, mother, siblings, help would be offered under the same terms, with the understanding that certain social expectations might cause her to feel more obligated. We would share Christmas day with her family, and either the day before or after with mine (if we went at all).
Physical help and financial help was never offered outside the family if it interfered with that of my own family. However, we, more often than any other members of either family, would bring help. As parents got older, we purposed to extend help with matters of finances (paying electric or heating bills) and although politely rejected at times, we made certain that the pantry had food, the house was cleaned, the repairs done.
As I have gotten older, my children now do the same.
But not once, is the extension done without the approval of the partner.
What if the family takes advantage of the goodness of another family member so that it interferes in the marriage?
Then it is imperative that the husband and wife learn to say, "No," or "Not today," or "Well, that is a plan, but it is going to have to wait."
We have had occasion in which to use those types of statements.
It is very important that the wife be able to say, "My husband...." and she find both safety and security from family and or members that want her to disregard the principles and stand she and her husband have established.
If such does occur, then (imo) it is important that her or his family understand that no further communication will take place unless both are present or are informed. The family must stand in unity from the influence of others who would desire to cause confusion or disloyalty.
Hope this helps.