I have written on this before, but I will give my little rant about obligations to family for any new or lurker expats that may be reading this. The east vs west unwritten traditions leads to a lot of strife. This is in my study of Indonesia and anyone is free to disagree with me.
There are times when cultural obligations will obligate a foreigner to financially support an in-law, such as providing a place to live. These are generally unwritten rules in most of Indonesia and more generally across all of Asia. There are times when families will use a foreigners misunderstanding of culture to take advantage of him or her financially.
Indonesian culture is less gender neutral than western society. There are normal gender roles in most Indonesian cultures. It is usually the male son's obligation to care for his parents. It can be stronger or weaker depending upon the ethnic background of the different Indonesian groups, but it seems to run through most in Indonesia. Women usually become part of the husband's family and it is his job to care for his parents and her to support him. This is most pronounced in Indonesian cultures that require a dowry or bride price. The bride price is to directly compensate the parents for the cost of raising a daughter and that she and the foreigner has no obligation to take care of them after that. The reality of the practice in the eastern islands is this is carried as a debt and paid off over time.
The gender difference is most evident in the treatment difference of son's and daughters in many Indonesian families. If there is a question of enough resources for things such as education or starting a business, they will usually go to the son over the daughter. This can even come down to basic discipline in the son being treated better than the daughter. Over the years I have had to listen to many an Indonesian woman bemoan this difference in treatment.
If a foreign woman marries an Indonesian man, especially if he is the eldest child, expect it to be both of the foreigner's and husband's responsibility to care for his parents and possibly any siblings if the parents have passed or retired.
If a foreigner marries an Indonesian daughter that has no male siblings, expect the foreigner to have financially support her parents and possibly siblings if she is the eldest child. This is a cultural understanding that every foreigner should know before marrying. I have known many Indonesians women that will confirm this in an indirect way. Since the foreigner doesn't understand the cultural context it will usually be along the lines of "I am not rich or I am an only child or I support my sibling, etc." followed by "do you still want me?" The cultural context combined with the indirect way Indonesians communicate, these questions are asking if the foreigner is ok with supporting family members. It flies right by many foreigners.
If there is an oldest son in the family, and it is a foreign male marrying a daughter, there is not a cultural obligation to support family members, especially not the eldest son. There may be a general obligation for anyone in the family to do what they can, but it is generally culturally acceptable to say no. Many Indonesian daughters will still attempt this despite it not being a social obligation. In my experience, I have noticed two common reasons. The first is the strong influence Indonesian parents have in the control and lives of their children. The second reason is after the years of being treated as less important, it is very empowering for women to be the one their family is financially dependent on. In these situations, it is more of an individual family dynamic than a broader cultural one.
An exception to the foreigner not having a financial obligation is if the foreigner starts acting like the defacto head of the extended family. If he is directing the family members what to do and acting like he is in charge of everything, then it is his social obligation to financially support it.