Ex texted my bestfriend and the convo was so weird…what could be the reason?

So my best friend and I are very close…my ex has no connection to her except me…after 2 months of full no contact and me finally not texting him…he texted my bestie saying “heyy..”
Then we were extremely shocked to know he texted
He asked her about her work and did small talk , then ended with a dry ass reply
We thought it might be something related to me but he just did nothing .
Why would he do this…when he knew how hard was the breakup for me ( I was dumped) and I was a mess for months
I hate that they think it’s okay to act like this
Do they do it for attention, validation?