Almost anywhere in Austria will fit the bill. As you have never done this type of holiday before, it is a good idea to use one of the Tour Operators to organise everything - flights, hotels, transfers and ski rental, lift pass and lessons for your son.
Look at TUI, Inghams, Crystal or Heidi - most of the hotels from mid-range and upwards will have "wellness" spas, which might include a pool, sauna, steam room, massages, treatments etc.
As pp^^ has said, group lessons in ski school in Austria are 2 hours in the morning, then lunch (usually somewhere on the mountain) and then 2 hours in the afternoon. He'll be in a group with other beginners, which can be great fun.
If the weather is good it is often warm enough to sit on a terrace or in a deck chair at a mountain restaurant, and many resorts offer reduced-price lift tickets for non-skiers so you can easily ride up to these restaurants to enjoy the view.