Let me add on to what
@PARIKRAMA has said.
One has to realise that CPEC notwithstanding, SAARC was a forum where Pakistan could have played a very significant role as a partner of equal stature on it's economic might in the region. However, by relying extensively on CPEC alone, it effectively has left itself completely reliant on the project.
On the other hand, by engaging the remaining countries less Pakistan and getting Myanmar and Thailand into the fold, what India has done is created a bigger bloc to effectively engage with China.
Members have to realise that international politics have no permanent friends or foes, only permanent interests. All international relationships between the nations are in shades of grey, you can not and will not be able to classify them either as black or white, as each nation is looking after it's interests either by aligning with your interests or by opposing them.
All such actions are transient.
By forming an alternate block and inviting them to BRICS, India has effectively provided and alternate, which is equally appealing if not more to China.
What matters to China, is access to markets, and alternate route to Indian Ocean. This block can provide that to China too.
Just a speculation here. But one needs to think on these terms.