Helping sibling financially when her and her SO refuse to make a budget...

Jess • I wear lots of hats.
Im in a pickle... My sister called me upset today saying she doesn't have any food for my 1.5 year old niece... She doesnt qualify for food stamps because her SO makes too much money (80% of which goes to his drug addicted ex and other 4 children)... They live off of 1300 a month where 950 goes to rent and the rest goes to bills... My dad and i have been sending money here and there to help them make ends meet.. Adding up to about 2500 total for the past 3 months... He buys 3 monster energy drinks a day, smokes, and eats mcdonalds every day and then my sister calls and says they dont have money... I feel frustrated because its putting a strain on my relationship with my husband because he doesnt find it nescessary to send them money if they dont build a budget and keep off of the "luxurie items" .. I agree... Shes trying to find a job but its taking a while... But when she calls you saying she doesnt have moeny to feed your niece.. What should i do? I dont wamt my dad to foot the bill himself... What would you do if you were in my shoes??