It’s old crap that chipped rather easily. They should be grateful this happened now, and they can choose a new counter top.
I’d bring them a few sample counter tops. If they go shopping, they are likely to find something very expensive, or in poor taste.
Plastics do become brittle with time - it is a fact. The countertop has a limited life span… so it is likely to be on its last legs anyway. Do they want to scramble when it suddenly fails big time (like when the integrated sink cracks) or do they want to get it replaced now while the cheap and experienced help is around?
I dodged a bullet!! I called the owner and explained the chips in bathroom counter and solutions to fix the chips. He said “Don’t bother, please just sand them a bit so they are safe”. He is so nice, I’m grateful we don’t have to spend forever working on a solution.
But for the future I found out how to repair. You get under the countertop and find an edge somewhere under the cabinet. Using a utilty knife you shave off pieces of counter and make a “dust”. Mix the dust with clear epoxy and form an edge with tape. Apply and sand when dry. The plastic dust should match the color pretty good.
Learn something new every day, whether I want to or not. My electrician shared that tip when he saw us pondering the chips
I was going to suggest cutting a piece of countertop somewhere under the sink and glueing it into the chipped spots… dust sounds even better!
He’s okay with a chipped counter top next to a Toto toilet? smh
CB, there are Corian repair kits that do not require shaping with tape - the epoxy base is thick like palydough. Hope you will never need to repair a plastic vanity top anywhere!! Those things are terrible.
I still would get the price for a new counter/sink. It can’t be that much…and really…it will add to the room in a big way. I mean really…how much could it cost? I’m not talking top of the line…but I’m talking new.
IMO, even a new Formica counter would be a luxurious replacement! That plastic stuff is sooo depressing to look at. But alas, CB is not driving that ship.
I’m not sure the old wood vanities deserve a new countertop:) they are beat up and have a mildew smell.
Since we vaulted the entry ceiling, the owners need to find a nice hanging chandelier for the entry. They also need a new dining lamp. They sent a link to what they have selected from Lowes. I didn’t say anything because it’s none of my business. But their daughter saw it and told them gently “they can do better than that”. So she’s off searching the Internet to get the lighting we need to install. She’s trying to run interference for me
^^ Once the new owners experience the soft close doors and drawers in the kitchen they will hate those old vanities in the bathrooms.
I like that the daughter is stepping in. Maybe she can gently inoculate them with the idea that the vanities are a disaster waiting to happen? 
Today we installed the giant sliding door in the gaping hole in the family room. We are finally totally secured. We have had the back of the house wide open for several weeks now. I was concerned that critters would get in but we haven’t had any issues at all.
But now those valuable carousel horses are safe!
CB…how much would a new bathroom vanity and counter cost? Are these folks being penny wise and pound foolish?
the vanity configuration in the master bath is odd and probably cannot be recreated with stock vanities.
The vanity and countertop in hall bath is long so lowest cost to replace would probably be $2,200 which includes labor to replumb and new faucets.
I did tell them we were going to go through the whole house and replace angle valves and old hoses because they were frozen and / or corroded.
Daughter fully realizes that she will be renovating the bathrooms in the future to sell the house.
I have low hopes that these rotted vanities will last that long…
Get some Shockwave and spray down the vanities and other old surfaces in the bathrooms.
That should take out any smell and kill anything growing there. They use this stuff in hospitals as a sanitizer/disinfectant.
I used this in the basement of my Cape Cod house, it works really well.
https://www.amazon.com/Fiberlock-8310-Shockwave-Concentrate-Cleaner/dp/B00U83A98M
Thanks for the product recommendation. I’m sure I can use that for many things I encounter in my glamorous job