In Laws problems

Hello, I need advice..

So my half Sister in law is asking for money to build a own house in our country (ASIA) not here in the USA tho. My wife’s half sister is in another country (Asia) and her another full blood siblings is here in the US together with her parents (IN LAWS). so we are living in a same roof with her family, My wife is FULL TIME NURSE and we live a simple life as a married couple. We travel a lot and we have bills, were just renting a house . My wife is paying the rent we were staying supposed to be her parents and sibling is sharing the responsibility but no and half of house billls and other responsibilities and everything. HER siblings is not helping us either in terms of house hold chores. the other sibling don’t have a JOB and she’s 31 ALREADY. She’s always in her room that’s it nothing at all. MOM and DAD (IN LAWS) is taking her responsibility, they spoiling her so much, They spoon feeding her as if shes still a baby.. and my in Laws are OLD now. and US? my wife and I we’re trying so hard to save for our future coz were in the 30’s now. we started a family late.. so were trying to save as much as we can for our future to buy our own house coz I wanna move out so bad, I cant handle them anymore, I don’t have a peace of mind, and offcourse I want to have baby.

NOW MY HALF SISTER IN LAW is asking my wife’s money just to build a own house in our country and she don’t have a JOB since BIRTH and She is already 40+ years old. My Wife’s Family has a legal business tho in our country “Apartment” so she’s incharge and taking care in that Apartment thats where she got her savings too.

NOW… AM I TOO SELFISH??? DO I HAVE TO RIGHT TO SAY TO NO to her request in using my wife’s money? COZ THAT’S OUR MONEY TO BEGIN WITH and in moving out???.. HOW CAN I SAY NO TO MY IN LAWS IN POLITE WAY. WE’VE BEEN DISCUSSING THIS TO MY WIFE BUT sometimes my wife is to soft for them. she can’t even say no sometimes. HER HALF SISTER IS FORCING HER so much.