Aveeno is entirely safe to use daily. The cream has only been available over the counter in GB recently, but all the Aveeno products have been available on prescription for years.
You can use it in conjunction with steroid creams or ointments, but works well on its own. My DS used it. We went on holiday one year when he was 5, and I forgot his steroid cream. He had a flare up on his legs, and the sea water made them sting. I bathed him every evening with the bath powder, half a sachet in a shallow bath, which he had to lie in for 20 mins. Afterwards I applied the body cream all over, although his arms and legs were worst affected. Within 3 days his skin had improved so much, and raw areas healed, that he could play on the sand and go in the sea with no problems. Admittedly, the moisturising effect of sun cream helped as well.
The bath powders are still prescription only, but for a child it is worth getting as it will be free. They certainly work well at controlling itching. Hot weather sweating was one of the greatest sources of irritation but central heating dries the skin out too. Combined with the cream they are great, also don't smell horrid. Keeping the skin well moisturised can reduce the amount of steroid creams you need to use, and the frequency of flare ups. We found it was best to apply the ointment first to sore patches only, and Aveeno over the top, immediately after the bath.
For Crabby's baby, if using a baby bath still, you will only need a quarter of a sachet, as the 'dosage' is one sachet in an adult full bath. But I used half the sachet in a shallow big bath, and you need to immerse all affected areas or at least swill the bath water over frequently for 15 mins minimum. You may be able to distract a baby with bath toys for long enough, but you have to clean bath and toys afterwards, as there is a bit of residue. If you want to apply the cream twice a day, at the time you're not giving a bath, give a brief wash to remove any sweat, grime etc. and then apply. You may not even need to bath baby daily when the skin is in good condition, just an all over wash and moisturise. There may be a lotion available too, might be useful for nappy area cleansing. My DS had 2-3 baths a week, the daily holiday baths with Aveeno were an extreme healing treatment.
If not getting Aveeno on prescription, Crabby, I urge you to do so! Skin conditions can be extremely expensive to care for long term.