Hi
the Kinderhotels are a German Austrian marketing chain of a group of independent child-friendly hotels . They have recently decided to extend their marketing efforts to the English-speaking markets. Standards in each hotel are different but they generally strive to accommodate the affluent family market.
I have no personal experience of the particular hotel you are planning to visit, but I have read a glowing report of it on rollercoaster.ie (parenting forum) from another Irish family who holidayed there last year. It is set in the countryside about 20Km from Salzburg, yet in the less sexy holiday area of Upper Bavaria. From what I read it caters fantastically well for the under 10s. If you are looking for striking Alpine mountain scenery etc, this is not the place as the mountains nearby are more rolling' and lower, but it is certainly picturesque.
For what it's worth, there are many ordinary hotels in Austria/Germany catering to the family market. Many hotels are just called 'family-friendly' and offer half board with apartments or interconnecting rooms. Many hotel with 'sport' in the name also have extensive facilities such as tennis courts, pool etc. Another family orientated chain is the Familotel chain (an excellent example of one of these, very highly rated personally is the Furtherwirt in St Johann in Tirol. ) English is widely spoken in the hotel industry in Germany and austria.
Hth