Can you get IHG points post stay?

[PLANT]

Hi all,

Family members were members for many years due to work stays. Have not used in last 4 years.
They stayed in Crowne in Dublin for a night but I don't think they added their IHG details on booking or checkin.
I only found out today....
Can they claim their points for the stay after checkout?
What is the process?
I have emailed IHG directly but seeking any experiences here.

 

[oz_mark]

There's a missing points form for stays in the past six months