is " to " necessary ?

[njanja]

Is it necessary to use " to " in the following sentence ?


They asked their friends for help, but they didn`t want to talk to them let alone
TO help them.

or


They asked their friends for help,but they didn`t want to talk to them let alone help them.

Thank you all ........

1st is definitely wrong

i would guess:

"They asked their friends for help, but they didn't even want to talk to them, let alone help them"