Bricks, Masonry, Asphalt and Concrete - Foundation wall below grade

Recently bought a house on a hill side with a walk out finished basement. Decided to relay the patio at the rear of the house. When I dug down I discovered a poured concrete foundation is 5ft below grade. This 5ft area was sided with broken asbestos tiles/ cement board. I have removed these. It is not possible to reduce all the grade by 5ft or install drainage pipe to daylight. How can I side this area. Thought about building the foundation wall up a little with cement blocks and framing it above this. Worried about the weight if I brick it up all the way.On to this frame I would attach cement board and waterproof it in some way and then backfill it. In addition is it ok to use mortar around the posts the house is built on which come up from the foundation. I cannot afford to pour a new foundation. Drainage is good and no signs of water problems in Basement. Your help is appreciated.