My own DH is just as bad. I talk to his mother far more often than he does, he says she 'just witters on' although he does love her very much, he simply doesn't feel the need for regular communication in the way that she (- and indeed I) does. She phones once a week at the very least to stay in touch, at what are often very inconvenient times (such as when we are on our way to bed) and it was only the other day that I said that really, if he would only phone her at a time suitable to him once a week, then maybe he wouldn't get so irritated. He rather shamefacedly agreed.
I hoped that staying in contact by facebook would solve my own problems with her as she can talk for England, an hour at a time, but no. A message from me on facebook to her means that I must be sitting there with nothing to do and would therefore love an hour's chat - which in her case, means listening to her talk and me not getting in a word. Then she accuses me of not telling her anything! She isn't alone, she still has FiL.
Her other son says that when she rings, he pops the phone down, goes to nake a coffee and festches a book and just lets her ramble. They both think that unless she has something really important to tell them, not that she has been for a walk and seen a buzzard, or that she has a new vicar, they don't want to know. I keep hoping that I will be able to remember that when my son has really left home.