Hi Ceci,
My husband is not eldest. There is an elder brother, who had everything paid for - 5 years of overseas education + wedding expenses (from 46 tables of $688+++ to GDL to jewelry for his wife).
In the end, this elder brother only started giving allowance to my MIL (only $300/month) last year.
Reason - he migrated overseas, so MIL didnt chase him for allowance. My husband stay with her, see her every day, so she keeps asking him for allowance. That's what my husband thinks lah.
To be honest, my husband can afford to give his mom allowance. That's cos we don't have housing loan cos never buy yet, and we saved up like crazy so dun need to take up wedding loan.
It's not an issue of cannot afford, but more that my husband is not happy giving so much to his mom cos it takes away $ from our joint savings every month and he feels unfair that his 2 siblings only give $300/month (and is getting more monetary benefits like free wedding dinner and free overseas education + free childcare minder and free meals) and he is giving much much more.