At 6mo my dd was still feeding every 2-3 hours in the day and once or twice in the night. She is now 7.5mo and is only having 3 bf during the day and normally one in the night. I think i was in the habit of offering every 2 hours but when she started eating more solids and I stopped offering she didn't mind at all. I would have fed her if she had wanted it but she just didn't seem to notice the difference at all. It was done gradually over about a month too, she didn't just drop feeds overnight. Perhaps as you increase the solids just wait to be asked rather than offer a boob and you might be surprised how long he can go.
DD is slightly younger at 5 months but in the last week or so has started going longer between feeds.
I'm still offering her feeds at least every 3 hours and she will often take a feed but then promptly throw it back up if she wasn't really ready for it , so am taking that as a sign that she only needs what she is asking for!
Dc3 is 28w and needs feeding every 2.5 to 3 hours day and night and has not really taken to solids. Dc1 and 2 could do 4 or 5 hours in the day and 8 or 9 at night at that age but took to solids a bit quicker.The other 2 just started refusing feeds or taking less, so i don't think you need to consciously do anything about it.