They have two convictions of DUIs within a year
Depends on how many of them are convictions. Two convictions means you will be on an RDP for 1826 days (5 years).
If you only have one conviction/revocation, it’s a one year revocation. Anytime served on a statutory summary suspension reduces the revocation by a like amount.
You can apply for the RDP immediately but with two DUI’s in a year you aren’t going to get any relief right away.