About parents asking HUSBAND/WIFE for money... What do you think?

I m married and have a kid, me and my husband work full time and we also go to school. We know how economy is right now so we try to save as much as possible avoiding going out, summer vacations and working on a budget before we spend, thank god it has worked and we have our savings and live good. He is from El Salvador and I am Mexican and our parents stay in our countries, he sends 100.00 to his mom every month, and I am ok with that because she is a widowed, sick women and economy is way worse there than Mexico. On the other hand, my parents are younger they have each other and my 19 year old sister WITH HER HUSBAND and kid living at home, he works but she doesn't, she never did or have. Now, my mom asked me to send her 200.00 for her "vacations" so I sent her the money 2 days ago, I called yesterday and then she asked me for my husband he was there and she said my dad wanted to say hi to him, I handed the phone to my hubby, they were talking for like 30 min and i was wondering why my hubby was looking at me weird while on the phone, then I told him it was enough and to give me the phone, so he did and my dad was talking about stuff he wanted to buy and for that he was telling my husband that SINCE I HAD SENT MONEY TO MY MOM NOOOOWWW MY HUSBAND NEEDED TO SEND MONEY FOR HIM!!! I got really upset and embarred my dad was asking for money after I had just sent some, specially to my husband who has no obligations with them, he barely sends money to his mom!! I told my dad to stop doing that and instead go on and ask my sister's husband since he is saving to much on rent, food and babysitter unlike us. They think that because we live in USA we are rich! I really need to talk to him without getting him offended, I uderstand they are my parents and I need to help them but NOT EVEN WE GO ON VACATIONS! What should I do? Am I right on this feelings? What do i do?