At first a remark. It is not your tree; we have one big common tree on wihich we all collaborate.
If your mother is not living it is no problem to do that.
If your mother is living the EU privacy law from 2018 must be considered.
That means that nobody can control DNA data of somebody else. That mean you must create a profile for your mother and add her E-Mail address. Then she becomes a family member. Then she can enter the DNA details.
She can also add you to her trusted list or put you on the profile as second profile manger so that you have access to her profile.
