Very good advice given here so far.
I would also like to add some additional advice. It would be very helpful to exam your mother to determine what the best treatment would be. Here are some options:
1. Kenalog/Steroid Injections: if the scars are raised or "ropey" appearing these injections can help reduce their size and discomfort. Time may be a factor since her scars are already two years old.
2.IPL Laser : this form of laser can be very effective in reducing the redness of the scars and can be combined with other lasers to soften and contour the scars.
3.Botox Injections: have been used with noted success in reducing pain and discomfort in postsurgical scars. There have been clinical reports of scar size being reduced as well. I will also use Botox during some scar revisions to help reduce tension on the scar as it heals.
4.Silicone Gel Sheeting/Tape: special tape designed to help reduce appearance of scars. Most often used with keloids and early scars but some benefit may be gained in older scar.
5.Scar Revision: if your Mother's main concern is to improve the scars then a scar revision would be very helpful. At two years out she may have enough skin laxity near the scars to allow enough flap elevation to remove the scars entirely and allow a tension free closure (important for preventing any additional scars). This would not necessarily address her neck or jowls but it would improve the scars.
6.Facelift Revision: if your mother is not happy with the results of her facelift and the scars, she should have a revision facelift where her jowls and neck will be addressed along with the scarring. This would require more skin laxity than just a scar revision.
An exam would also help because if her concerns are mainly with her neck, than a Necklift and not a Facelift would better serve her.
Hope all this helps and that your Mother gets well taken care of.