Can anyone help me with any differences between those words? C-E dictionaries say "there's no way out" or "nothing can be done" for all of them, C-C dictionaries say about the same.
However, I was corrected using 莫可奈何 and 沒轍 wrong in these examples:
A: 都什麼時代了，你買還來相親這一套啊？！不過話是回來，天下父母心，做父母的總是為子女的終身大事，我也 【沒轍】，沒法幫你。真是難為你了。
I put 沒轍 for 莫可奈何 and vice versa. Can anyone explain the different notions of these two words? I added 沒辦法 as well, because maybe there are some similarities.
Thanks for all the help.