There is currently one FDA approved drug to help treat ALS, Riluzole, but it only prolongs life for a few months.  Progression is very different from patient to patient and it cannot be predicted.  The average life expectancy after diagnosis is 2-5 years; While the man in this video has been surviving with ALS for 7 years and seems to be doing pretty well this is not common and in many cases like this things will take a turn for the worst very quickly.  

The most well known, and unusual case of ALS is Stephen Hawking.  Not only has he been living with ALS (or Motor Neuron Disease (MND), in the UK) for more than 40 years he was also diagnosed at the very young age of 21; Most patients are diagnosed between the age of 40 and 70.  Stephen Hawking is an inspiration to ALS patients everywhere and is a prime example of what he disease can do to the body while still leaving the mind in tact.