Is your mom interested in staying with this advisor? It might be best to switch to a different advisor who goes for a more passive investment approach (and charges less). Someone who could charge a flat fee for services rendered (and coming up with a tax-aware transition plan for you mother's portfolio could be a big and expensive service) rather than a percentage of her portfolio (because, honestly, it's not 10x more work to manage a $1M portfolio compared to a $100K portfolio).
I don't know much about the service or the pricing, but Vanguard does have
human advisors you can work with.
Also, if your mother can get her current advisor to help her transition to a simpler, more passive portfolio, she can then say, "thanks, bye!" and hold on to her investments (rebalancing and adjusting her risk tolerance as necessary). If that's the plan, she probably doesn't want to let the advisor know she's planning to dump her (although she might figure it out anyway) because then she doesn't have a whole lot of incentive to maximize her tax savings.
The advisor probably isn't deliberately doing anything evil or bad - I think a lot of financial advisors just want to show their clients that they're DOING SOMETHING (and they want to feel like they're DOING SOMETHING), and 36 holdings looks more like DOING SOMETHING than 5 holdings, even if the two portfolios perform almost identically.
FWIW, my company produces software that portfolio managers use to do tax-sensitive trading (and we're especially good at transition!) but we don't have a direct-to-consumer product and I think most of the advisors/managers who use our product charge the kinds of prices your mother is getting charged.
And finally: if the advisor gets you mother to invest her money rather than leaving it in cash, and can talk your mother out of pulling all her money out when the market takes a turn, that's worth a lot. Maybe not $7500 a year, but seriously, it's not nothing.