"let sb / yourself in for sth"??

[Dilmunis]

Dear teachers...
today my question is about a PHR V with LET.. let sb / yourself in for sth
I found this definition in the Oxford Dictionary for English Learners...
to involve sb/yourself in sth that is likely to be unpleasant or difficult: I volunteered to help, and then I thought ‘Oh no, what have I let myself in for!’
I have to give another example, so I have written this and don´t know if it is right:
His parents say this is an ordinary opportunity, so he will end up letting him in for what he doesn’t desire the most.
Well... Thank you!!! bye bye

[Tdol]

him in for what he doesn’t desire the most.
himself in for something he doesn't really want to do???