I don't want to make this an epic post, but a bit of background. SIL has always been a bit reckless with her money (and has married a DH who is even worse). DH has always been very sensible with money and has been very careful not to get into debt as he knew that his parents would pay it off, and he didn't think that that was right. SIL has one child, we have two. Both SIL and BIL work, as MIL provides free childcare. I am a SAHM to two children (childcare too expensive where we live) so even though DH has a good salary we have 4 on one income in an expensive area.
SIL and BIL have a lifestyle that we just can't afford (gym membership, new clothes, expensive hobbies, haircut and colour at salon, new furniture, holidays etc.). It turns out that they can't afford it either. But PILs bail them out at every opportunity. We know of very large sums of money that have gone to them to pay off credit cards etc. and BIL has told us in ear shot of FIL that he basically thinks of FIL as a cash machine. Part of this is that the ILs want to give their family money now, rather than leave an inheritance and not see the benefit of their cash while they're alive (fair enough). I know that it's their money, and if they wanted to leave it all to the Battersea Dogs Home then that would be their business. But FIL has just withdrawn an offer of money to us (to help buy a house) because we managed to strike a hard bargain and we have told him that while the money would be very welcome that he shouldn't feel obliged as we could sell off some investments (that were earmarked as university fees for the children). We feel as though fecklessness is rewarded at every turn, and that our care and thrift is punished.
Is there any tactful and non-greedy way of pointing out that DH feels that he is not treated as well as his sister?