Are you talking about a one bedroom, or a two bedroom?
If a two bedroom, then I say go for it. If a one bedroom, then it comes down to how much privacy you want from your mother. While there is a seperate bathroom area with a tub and sink, you would be sharing the toilet area.
Also depends on how picky you all are about sleeping arrangements...someone will have to sleep on the sofa bed, which I do not find very comfortable...but I am picky about mattreses.
We love the WL Villas and have stayed there four times. I LOVE having the washer and dryer in the room. Some people do not like to do laundry on vacation, but I love being able to pack very light. It is no big deal to me to do laundry. We also love having the kitchen.
Another thing we love about the villas are the bathrooms....we really like having the walk in shower, and the huge seperate tub.
The walk to the boat dock is not bad at all.
If it were me, the only way my family could share with my mother in law would be to stay in a two bedroom villa or 2 regular rooms. We prefer having a bit more privacy than a one bedroom villa would allow. But everyone is different in that regard....it comes down to how you persoanlly feel about sharing the space.