Question

he lost.....friends he had fill determiners (the few/a few)​

Answer 1

he lost the few friends

Answer 2

He lost the few friends he had.

• The correct determiner to be used in the blank is 'the few'.

• The word 'few' is a type of quantifier which is used along with plural countable nouns.  

• Addition of an article with this words adds meaning to it.

• For example: Addition of 'a'- 'a few'- refers to some. On removal of the article 'a', it refers to a small number of things.

• Again, if 'the' is added, it refers to something specific in addition.

• In this case, it refers to the specific friends ( small number) that the person had.