[Japanese > English] 〝もう呆れてものが言えない、お前の好きなようにしろ!〟

I am trying to understand the quotation at the end of this passage:

Context:

A young man with a university degree (in the early 1960s), who had worked as a stockbroker, quit his job and after 6 months being idle, accepted a job for an American owned company in Japan, where he would be a salesman for slot car racing tracks (model car racing for children).

His first month was spent managing a slot car track so he could learn about the product before selling it. When his parents found out what he was doing for work they were very upset, because all of his 6 brothers were more successful. They thought he was playing with children rather than looking for a real career.

At the end of this passage is a quote from his parent(s) that I am having difficulty understanding fully.

〝もう呆れてものが言えない、お前の好きなようにしろ!〟

Does this mean:

“I'm too stunned to say anything, just do whatever you want!”

or

“I’m too disgusted to say anything, you just do whatever you want!”

Any insight would be helpful.