together they have imposed the baggage on child that he cannot put down .who do they refer to what is the baggage and why can the child not get rid of it how is mukesh's attitude to the situation different from that of his family?

Herer 'they' refers to the other people of Mukesh's community who have lived their lives and are now at the end stage. 
Mukesh was having different attitude as he was willing to become a motor mechanic and was ready to work hard for it, inspite of the difficulties .