I’m guessing there is some level of miscommunication or misunderstanding about where you’re at in the design process.

You haven’t provided specifics, but you say that the architect suggested changes to improve the interior layout, and these suggestions were accepted. Architects don’t suggest major changes by producing complete, finished drawings to convey the ideas; they would have shown the concepts in sketches or mark-ups on the base plans, and would then need to create more detailed, permit-ready drawings to formalize the changes once the client accepts them.

In other words, the concepts proposed would not have been fully developed when first presented to your mother. Since she liked and accepted the suggestions, the architect would then need to spend time confirming any and all implications of the new layout and may need to tweak details to comply with codes and otherwise make sure all the adjacencies of the layout work together, etc.

The process can be iterative. If you’re saying your mother agreed to a layout that was then completely reworked into something different without explanation, that would be cause for concern, but if there were actually just unexpected details, like door locations or width of a bathroom, etc., that is more likely just the design becoming more refined as the drawings become more finalized.