Question

1. Thanks to his father, he succeded in his business.

Instead of 'thanks to' can we use 'because of' or 'owing to'? Are they the same in meaning? Does 'thanks to' have a positive connotation?

2. He retired from the work.
3. He retired from the workplace.
4. He retired from his job.
5. He retired from work.
6. He retired from the firm.
(Are they all gramamtical?)

Answer 1

All three of those expressions have essentially the same meaning, yes.

#2 is not correct, but all the others are.