Is it possible to replace the entire keyboard?

A friend of mine is hoping to be able to replace the entire keyboard on their Macbook Pro 15" Touch Bar 2018, they took the computer into apple to which they were told it would be a £700 to £800 dollar replacement. They told me that they were expecting it to an around £150 to £250 replacement cost. They themselves have replaced the fan in the computer but are unsure about trying the keyboard yet because they feel that they should have more knowledge first, such as, is it possible? Along with considering all other possible options. The reason that they wish to replace the keyboard is due to multiple issues, including, the 'up' arrow key is broken, W key has fallen off, and keys such as L and M keep jamming.