"Mom, look, fortunately, I didn't hesitate to spend the money, or else we would suffer once we reach S Province." Qin Yu didn't intend to belittle his mother.
He wanted his mother to understand that some money can be saved, but some can't.
Like this time, if they had chosen to save money by buying a sitting or standing ticket, they might have had to spend money on healthcare due to fatigue once they reached his sister's place, and they would perhaps have ended up spending more.
"Xiao Yu, I understand your sentiment, and I'm also glad now that I didn't opt to save that money and not get a sleeping berth." Nangong Shulan later compromised because of the love of her husband and the respect of her son.
Also, the money her elder daughter had sent home could alleviate their difficulties for a while.
Therefore, when her son bought the sleeper tickets, she only expressed her concern once, and did not insist on him returning them for sitting or standing tickets.