I haven't taught for a couple of years, but can't imagine things have changed that much....
I would expect a Y1 child to be group-reading probably twice a week (group reading session every day, teacher and TA, 5 groups of readers so twice in a week...). I would expect there to be group reading records, where the adult records what the focus was for the reading group (particular phonics, key words, strategies practised etc) and quick notes on individual progress, which then builds into a good record of where children are. I used to check through these sheets at the end of each week, and set new targets to focus on for the following week. Home reading books were changed usually twice a week by myself or the TA whilst we had our group, but parents could also change them at other times if they felt the need.
I wouldn't hear every child read individually (hugely beneficial for the child, but simply not time-effective for me as a teacher) although I would certainly read individually at the beginning of each half-term to get a good feel for each child's needs. Every school I've worked in has had parents and volunteers in, so, with the TAs helping as well, each child should read 1:1 every week with someone, and yes, the weaker readers were usually heard more often.
I also used to gain alot of info about children's reading from the carpet session of the Literacy Hour - the bit where as a class we read a text, and introduce whatever it is we're focussing on, and general stuff that was going on everyday. I can also say that I would always have far more info in my head about individuals than was written down, so if you asked me about a child's reading I would be able to go on for ages, although not all of it would be recorded anywhere.
I did read your other thread. Sounds v poor to me, although in the teacher's defence Y1 is a hard year group to get right - the balance between pushing on the academics, but continuing to have a more play-based approach is tricky. And if she's new to that year group it can take a while to get routines and systems up and running. Having said that, though, I would definately expect Y1s to be reading in some shape or form every day (be it a phonics or computer game, topic based stuff, group reading or puzzles) and for the teacher to have a good grasp of where indiviuduals are in their reading by the 2nd or 3rd week in. Your ds' teacher should certainly be able to talk about the next steps needed in his reading progress with confidence 5 weeks into term........
And that turned into a bit of an essay...sorry!