need advice for reentering

[sr24r]

My in-laws 3 years multiple entry visa and visited US for 4 months out of the 6 months I-94 time period. Their I-94 expired in April and now we would like them to come again and visit us at the end of May. This time there will be 2 grandchildren along with them because of their summer vacation. Will my in-laws have problems at the border because they are coming back in less than 3 months after they left?

[peace]

They will face questioning as to why they returned so quickly.
With grandchildren with them they should be able to convince the officer that they have brought the children for their vacation and they will be returning in 2 months.
It is very important that they answer the question " How long do you wish to stay?" with the right answer. Just say 2 months or less.

[PraetorianXI]

Agree with peace.

They should not spend more than 6 months in the USA in any 12 month window.

Their visa may be cancelled and that would be a bad thing. Do not ask for more than 1-2 month stay and after that... wait at least 6 months before coming back.