I would also question the propriety and legality of creating an account for an adult child. Creating a FamilySearch account requires you to agree to the
FamilySearch Rights and Use Information, which includes this:
FamilySearch wrote:In consideration for the use of this site, you represent that (a) you have read and agree to the terms of this Agreement, and (b) that you are legally able to register (if required) to use this site and any other FamilySearch affiliated site. If you submit personal information to this site, you agree to provide true, accurate, current, and complete information about yourself (including during the registration process) and maintain and keep current and accurate this information about yourself, should it ever change. If you provide false, inaccurate, inappropriate, or libelous information or images, we may suspend or terminate your account and use of this site.
I don't see how you can honestly make those representations on behalf of someone else, unless you have power of attorney on their behalf.
Questions that can benefit the larger community should be asked in a public forum, not a private message.