My friend is upset because of her mother-in-law. What do you think?

My friend is in her late 20s and got married quite early.
Since it was her father-in-law's first birthday since the wedding, she was invited to her in-laws' house. She took a day off on Friday and spent the entire time until Saturday afternoon preparing the birthday meal.
It's a busy season at her work, and she even squeezed in time to get an IV drip because she was feeling a cold coming on.
Her sister-in-law drove her parents (in their early 60s) over, and the meal and atmosphere were good.
However, when the sister-in-law said, "Thank you so much~ where can you find someone like this these days?",
the mother-in-law replied, "You have to keep doing even better to keep getting praised~"
The sister-in-law was shocked and told her not to say things like that...
Also, the event was meant to celebrate both her father-in-law's birthday and her own recent promotion, but all mention of her promotion was completely skipped.
The sister-in-law had to leave early due to an urgent matter in the evening, and since the in-laws didn't bring a car, they stayed the night at the house.
My friend woke up at 7 AM to cook seaweed soup for them.
Then her husband drove them back to their home, which is 40 minutes away. Even though she sat in the passenger seat and went along with them, they didn't even bother to tell her not to come...
When she got back, she slept like she had passed out all day.
She says she doesn't think she'll put this much effort into her in-laws' family in the future...
It seems like she is really hurt.