I'm not sure that's correct. AFAIK, having deep Oracle knowledge is very valuable to the right employer, but not so much for non-Oracle shops.

From my experience ~20 years ago, Oracle and SQL Server were very different beasts.

IIRC, once you get past trivial querying and into storage design, query optimization, etc., they're very different beasts. And Oracle in particular is it's own, huge world at that level. (Again, if I recall correctly.)

Sure, and I think that would definitely be relevant to a different kind/level of analyst. Sounds like OP’s mom would be more than covered by knowing how to google “Postgres function for whatever”.

I think for most SQL-only analysts, the vagaries of deep Oracle vs. MSSQL or whatever aren’t super relevant.

My own impression is that she who can write PL/SQL can write T-SQL. My own background is largely in Oracle, but I've dealt with SQL Server a fair bit.

I work with both Oracle and SQL Server, and this is absolutely true. There is a common standard you can stick to, but there is also a considerable universe of Oracle-specific features even just in the query language, to say nothing of temp tables etc.

Her title is db admin and that’s the position she’s gunning for. They’re going to expect senior level skill beyond just creating queries.

“ She wants to find a place to be comfy and write some SQL scripts, analysis, and data modeling here and there, where she will be both happy and useful. Pay is not a priority.”

None of this suggests senior level skill to me, whatever title is associated with it, particularly given the three points OP listed that she pushed back on. This role is, at most, mid-level.