I have a friend whose communication pattern over the many years I've known them can be summed up as - they take ages to reply to my texts (eg a month) but expect me to reply much sooner (maximum a week) before they text again to question if everything is ok. When they take ages to respond they never give an excuse - they've normalised it. Occasionally they'll message, I'll reply, they'll message back quickly for a few more messages and then randomly stop, drop the conversation and reply again after 2,3,4 weeks.
It's like they want to control when communication happens, when they'll swoop into my life and when they'll just disappear again without warning. They know that if they want to meet with me eg in September they just have to reach out a couple of weeks beforehand and it will be arranged whereas if I wanted to do the same the meet up would happen in November (accounting for the delay in their reply and their limited availability). Therefore I let them initiate every meet up (which happens a couple of times a year). It feels intentional since they're very aware and bothered when I delay replying even though it's much less of a delay from my part compared to their timing. I sense that there is some level of entitlement there.
I've never addressed it because I'm fairly sure the reaction would be very subtly demeaning/patronising, definitely uncomfortable for me and would probably make that person feel in demand.
Also, how would you break this pattern of communication/dynamic?