Tu nie ma relative clause.
My dad got a new job,and was obliged to change the place of living.
This is a
compound sentence made up of two
independent clauses --> it can be split into two
simple sentences: My dad got a new job. He was/My dad was obliged to change the place of living.
If omitting the pronoun is not confusing and it is clear who/what the subject of each independent clause is, you can omit the pronoun.