First of all - there is nothing you could have done to 'prevent' this.
I have a severely dyslexic DD (now 14). I'm hyperlexic, but DH is mildly dyslexic and there are family members on both sides with dyslexia. DD grew up in a house full of books - she had all my old children's books plus all the ones I bought... I possibly had more than most local libraries. She was read to endlessly as a child, and we just expected that she'd start reading herself around 2 and it would be effortless. DH and I are both writers and so the house is full of books and magazines and everything you could possibly want to instil a love of books and reading.
Instead she didn't learn to read at all until she was 7, refused to even contemplate anything involving letters at all (we had fridge letters, pointed out things on signs, I was a SAHM till she went to school and spent almost everyday in a different museum or 'learning experience').
She loved books - but just made the stories up based on the pictures.
Teacher at primary who was very dyslexic himself picked up on it and they had a full report done by the school's ed psych as soon as she was old enough.
We did Nessy, we did Toe-By-Toe, we bought weird pencils, we bought overlays. None of it really helped much.
What did help was lots of high quality films (Secret Garden, Narnia, Harry Potter, 5 Children & It, Beatrix Potter etc) and then getting her touch typing in Y6 and moving to a laptop for everything.
DD still doesn't read for pleasure, but she has an incredible vocabulary and is considered gifted at creative writing. She can't spell at all - but there are computer programmes that can do that for you, so we have focused on teaching her to use those. There is also speech to text software - DD won't try it but I have friends whose kids love it.
DD probably won't achieve the exam grades she would without the dyslexia, but then there are other things she's very good at like music which may actually be helped by her brain working in a weird way.
I would recommend getting a full diagnosis if possible as it's very useful to know where the problem areas are so you can focus on those.
Also what works for one child may or may not work for another - depending on where the issue lies and on their personality.