I'm going to ignore my mother and brother after I leave.
Why would you ignore them?
I don't want to hear their complaints about me.
Ignoring them could be the reason the complain. You shouldn't ignore family unless there is an extremely good reason.
Stuff it, I'm going to go eat instead.
I'm just trying to say that the reason for them being frustrated with you might be really obvious. How about this time after you eat, try asking them what's wrong instead of dismissing them?