Whilst I can understand your worries and concern, as others have written, its not as bad as it would be if your daughter was in, say, y6 or y11.
”Well I know this has been an ongoing issue with this teacher, so I expect the school to get another teacher in.”
A school can’t just get rid of someone - schools have to obey employment law. (At least in the UK.).
In general…. 6 months off on full pay ( with doctors notes etc.) 6-12 months on half pay. At that point you can be dismissed for incompetency - because you’re not well enough.
If a teacher is away a week, back, then off the clock doesn’t restart.
If one is seriously ill then you can ask to retire through ill health.
Some schools pay into an insurance scheme to pay for cover. But some can’t afford it/hope that no-one is ill/pay as they go/ cover it internally using TAs and teaching staff loosing their non-contact time.
I’m not sure if you know exactly why your daughter’s teacher is off? In my experience few are off for minor reasons.
Some ailments, like my wife’s cancer needed a straight 7 months off. Some struggle back, out of a sense of duty, between chemo treatments.
Some conditions flare up, requiring time off periodically
To my mind, pain as it is it’s probably best not to complain unless you know all the facts - and even then………