I'm not sure what you mean, or perhaps you have an incorrect understanding of how Haskell works. Of course data is still checked at runtime; for example a parser will check that a string is formatted in valid way, or a lookup in a hash table will check that a key is valid. This is done at runtime as it would be in virtually any language.
However there's no way in Haskell (short of low-level type system tricks) to check that a function with an argument of type `Int` actually receives an `Int` when it is called. There's no need to, because it is guaranteed by the type system. The strength of these guarantees, coupled with the ability to define rich, expressive types, are what makes Haskell programs very robust. For example you can represent all possible results of a valid JSON parse:
data Value
= Object (HashMap Text Value)
| Array (Vector Value)
| String Text
| Number Float
| Bool Bool
| Null
Which variant of this type is actually encountered will not be determined until runtime, so the program is required to respond to the different cases; however a function which takes type `Value` will never need to worry that it doesn't actually receive one of the above variants at runtime.
Sounds like writing him a new, attractive, professional resume could be very helpful. Clearly his biggest issues are dealing with people and presenting himself.
Side note: that he could live at all in San Francisco on that kind of income is truly impressive. At $1600 a month, rent alone is over $17000 a year.
However there's no way in Haskell (short of low-level type system tricks) to check that a function with an argument of type `Int` actually receives an `Int` when it is called. There's no need to, because it is guaranteed by the type system. The strength of these guarantees, coupled with the ability to define rich, expressive types, are what makes Haskell programs very robust. For example you can represent all possible results of a valid JSON parse:
Which variant of this type is actually encountered will not be determined until runtime, so the program is required to respond to the different cases; however a function which takes type `Value` will never need to worry that it doesn't actually receive one of the above variants at runtime.