Am I wrong for this???

Soo my brother in laws car is messed up (engine). He has been trying to get it fixed for almost a year now, but hasn’t had a chance because of money issues he’s 28. About a week ago my brother in law got his $600 dollar stimulus check. That same day my mother in law told him to get it towed over to the mechanic which he did. I did mention to her not to get it towed because we where 100%sure it was the engine and it was going to cost over $2000 to get it fixed and they did not have the money. My mother in law reassured me that she was going to work over time to make sure she had the money so I was like ok fine. The only reason I told my mother in law to wait was because she has a history of making decisions with out thinking and always coming to me and my husband for money and to get her out of the hole she puts herself in. Sure enough the mechanic called me (her phone has no service )the following day and said it was going to cost $2300. I once again asked her if she wanted to wait and she said no,so I let the mechanic know to go ahead and fix it..Yesterday she texted my husband to see if we would loan her $500 dollars for the car because “she forgot she had to pay her light and cable”. I also asked her what happened to the rest of the 600 my brother in law got, and she replied “oh that’s been gone”. I was pissed off as you can imagine. So I told my husband that I was not ok with it because she had told me she was going to pay for it..Now she saying she will pay it back 2 weeks to a month from now. First of all I don’t believe her because rent is coming and I can already see her saying she won’t be able to because of it.She lives with her other 2 sons one is 19 and the other one is 28 they both have jobs and it frustrates me that she dose that make them help her out, but here we are helping her out. My husband is the only one working because I’m a stay at home mom. We have a shit ton of bills to pay like credit cards,rent, insurance, food etc..and our 2 cars need maintenance also. I don’t find it fair that we have to put our shit on hold because of her..it’s so easy for her to just come and ask for money all the time..and like I said I don’t mind helping but omg she does it on the weekly basis it’s annoying. To top that off we also yeah also helped her other son (19) to get a car..We bought him a cash car because he had a baby on the way and needed it. He’s also paying us 400 a month(that’s a whole different story). The other issue is that my husband does not see anything wrong with this and always lets me know that it’s his money not mine because he’s the one working and goes off saying everything in this house is his because I didn’t put shit in..and that’s his family and will always help them out no matter what i say.. But then I’m like well then y the fuck are we married then if shit I say don’t matter. We are currently not talking because if this. I understand everyone has problems financially but she does it a lot and does not care because she had my husband to help her out. Am I wrong or is she crossing the line?

Sorry for the long story but I just needed to vent because I have no friends..😓 also excuse my grammar..