Being the shitty friend

I've been the shitty friend, we all have. By shitty friend I mean, the one who doesn't call, who can't be bothered, who treats people unfairly and seems to not care. Truthfully I care. We all have shitty friends. The ones we wonder sometimes why we're still friends.
 Take my friend A, he's useless at keeping in touch, loses his phone, never checks his facebook messages, never returns voicemails, emails, pigeon post etc. When you make plans, he's always late, and sometimes just doesn't turn up. And yes, I get annoyed with him. We've been really close, and it feels like we're drifting, mostly cos I never speak to, or see him. He's been through a lot with his family and things.
I get that sometimes the stuff takes over and makes it harder for us to connect with the world. I really do. I've been there, there have been times when I don't want to see or speak to anyone, let alone be a social butterfly. I also know it can be intensely lonely when you isolate yourself from the people you care about and who care for you.
But sometimes being the shitty friend is not being the one who calls, I know he never calls, so I just stop trying and that doesn't make me the shitty friend. It's tough, and I feel guilty. So tonight I'm going to call the numbers I have for him and attempt to check in and catch up, maybe make a plan. It's time to stop seeing how shitty other people are and stop behaving like that myself, it doesn't fix anything and it makes me feel bad.