That sounds like a fairly usual level of communication between a young man and his parents to be honest.
I loved my mum a great deal, but we'd only generally have a chat on the phone once a week or so if I wasn't going to be seeing her. If I was seeing her that week, that would replace the phone call. We might exchange a couple of texts in that time as well, but usually only to send each other links we might find interesting, or, "Do you fancy seeing this in the cinema next week", something like that.
Yes, sometimes we'd talk more often, for instance if Christmas was coming up, or arranging to go down and see my brother, or if family were coming to visit us, or when she was ill.
But aside from that, whats the need for daily communication? I'd really struggle for conversation with her when I did see her if I was sending messages back and forth all week.
I can't really imagine ever being in that close conversation with anyone aside from DP, and even next week when I'm going on holiday alone, I probably won't speak to her daily. Even DD when she goes to uni later this year I won't expect to hear from more than about once a week after the first week or so.
DP is the opposite. She can speak to her sister for an hour on the phone, and then do it again and find a whole new set of conversations to have. That's just not something I'm capable of frankly!