This is not Adobe. Rather user to user forum.
For the definitive answer, please consider contacting online Adobe Chat at the following link related to Account Information.
I have browsed through that Adobe Licensing Agreement and did not see that the definition of "customer" extended to the details that you are asking about.
You are allowed to install your software (one licence) on two machines.
Weather its two windows, 2 macs or 1 window and on mac machine.
If they are in the same household..........
If the family member lives on the other side of town that is another matter.
A point of distinction here which is not really part of the question that I believe that you are asking. But since it was pointed to...
It is the purchased activated serial number that you cannot have on more than 2 of your computers. And, you are not supposed to use both of these 2 computers at the same time.
But, you can have a deactivated installed program on many computers.
For example, if you had the purchased activated serial number on 2 of your computes and you want to install and use that serial number for a 3rd computer activation, you would deactivate one of the other 2 programs. But, you do not have to uninstall those programs from that other computer where you just deactivated Premiere Elements. Uninstall is not the same as deactivate.