Alliant is moderately conservative, so with such a short history and low CL's, I don't think they would approve for a very large CL (I think $5k is unlikely).
Also, Alliant is not a "prime" card, so if your originally stated objectives stand, this would not meet that. However, Alliant is an excellent CU and a great place to build a relationship.
But for now? are there any good cards he could be approved on?
Let the accounts age.
What is his objective? He can apply for a couple but will get low CLs and probable denials.
If he waits till all are a year or so old he will get more approvals and higher limits.
He pretty much has "Prime" cards now just not Super Prime.
He should wait, keep utilization under 20%.
Is there something he is trying to accrue credit for?