If you have time, go to Vietnam, Hoi An to custom make one suit. It's really nice and much cheaper than local tailor. For the price of a full suit at Lord's for example you can have your suit and a full holiday there. Can get your brother to do his suit there also, go whole family.

If no time or budget, H&M blazers cutting look good and modern enough, quite cheap too. Honestly, Malaysia weddings I find blazer and black jeans/pants with nice shoes is more than enough. Most important is fit and cutting