@Tiredmumtoboy tagging so you will definitely see this!
OK, do you know what letters they start with in his scheme? You can ask his teacher if you don't know. And do tell her you are dyslexic and there is dyslexia on the other side of the family too.
You could do a jumping/running game. Whatever the first three letters he learns at school are (ours were S A T), print or draw them absolutely giant on A4 paper (you could draw them and he could help colour them in if he'd like that). Put one on a chair seat, one on the floor and the other also on the floor but a distance away. You can do more than one of each letter and have them all over the place if that would be fun. On the back of the sofa etc! The game is that you make the letter sound (so SSS not saying ess) and he has to jump on or run to the paper with that letter. Put a little bit of music on if that's not distracting, something that doesn't have words, not too loud, and do it on a rhythm once he starts to get the hang of the first few. Rewards for trying. Bigger rewards for getting it right - maybe a marble jar or similar with one marble for trying and two for getting it right and when it's filled he gets something little he'd like?
You could make a pile of snap cards with S A T P I N (or any other letters/sounds and include E/letters in his name since he knows them, but lots of each one) and just work on seeing that one S is the same as another S, with lots of praise whenever he gets it right or is really making a good effort/concentrating. You need lots of each one so there will be lots of matches. Then move on to saying the sound when you pick up the cards if he can see that S and S are the same or P and P or whatever. Obviously let him win if you possibly can. You could print these out in big bold type on card so they look all the same. The goal here is just to recognise that one S is the same as the other S to begin with. The sounds can come after that.
You can get some magnetic letters and stick them on a radiator in another room. Game is that you say the sound and he has to run and pick you the letter and bring it back. Points for speed! If he can't do it, he can come and ask for a clue about the shape of the letter. You might need a few sets so that he can have a few of the ones he knows to begin with. Once he starts to get the hang of you, you can time him if he'd find that fun. Never say he got it wrong! Say 'nearly right, do you want to have another go, here's a clue'.
You could make some homemade dominoes out of card with the letters and play dominoes matching those. Again, say the sound of the letter not the name when you put it down to match another.
Since he already knows some of the letters in his name, perhaps start with those in whichever game he would like best, and introduce one more at a time only moving on when he has that extra letter down pat. Try to do lots of things that he can get right! It's important that he feels successful. Switch the games up so he doesn't get bored. And drop any of the games that are not enjoyable for him.
And it's also important to stick to the letter sounds not the letter names at first as that is how they'll be doing it at school. If you are not confident with the sounds, the Jolly Phonics videos I mentioned before might help (though sitting through them without your son may be a trial).
I don't think it would be a bad idea to ask the teacher for support since you are dyslexic. Usually schools run sessions about how to support with literacy and maths at home etc so might be worth asking if there will be any of these in the near future.
Sorry, that was insanely long, hope some of it is helpful.