Ds's father and I broke up whilst I was pregnant (he went off with someone else) and he moved abroad when ds was 3. I've always been welcoming to ds's grandparents but his granny is a tad on the meddling side so it's been a case of gritting my teeth sometimes. We moved house a couple of years ago to be closer to ds's school (he's 15) and she hasn't come to see us at all, despite having family three miles away (we moved 15 miles out, I don't drive but she does so it's not far for her to come). She hasn't called (my phone number's been the same for 16 years), hasn't emailed (she has my email address, I've emailed her to let her know how ds is and she's never replied so I gave up after 6 months), and the last letter she sent was attached with a newspaper article about funding for a boarding school. We've been back to the old town a couple of times and have met up with her there but there's no other reason for us to go and I don't really have the time to do this as I work weekends and during the week, I also have MS so am not always able to run around on my days off.
It was ds's birthday yesterday and she's sent him a card, saying how much she misses him and how she only has old pictures of him and she doesn't know what he looks like 
. She's said that she'll send him some money when he gets in touch as she doesn't know if she has the right address for us.
She's quite hard work, she'll ignore ds and will interrupt him to talk about random things when he's trying to talk to her or me. I've seen her smack her granddaughter across the back of the legs for dragging a brolly across the floor but later she deny's hitting her gc. This is also the woman who went into ds's primary unannounced and asked for a copy of his school reports because I didn't give her any information about how he was doing. She also used to collect him without being asked, I could go on.
I'm quite pissed off to be honest. I'm happy she's sent ds a card and she's told him that she's thinking of him, but surely it shouldn't be always down to me to sort contact out? Ds doesn't see his father as he's been verbally abusive previously. He also only used to visit every 18 months - 3 years for an hour so she'd never see ds at all if his father was left to sort this out.
What do I do?
Thank you for listening to me moan 