My friend has MS her hubby is her caregiver and is up all night taking her to the bathroom

I don't know if a foley cathete is the solution for your friend, but I know there are some high-performance overnight disposable incontinence products which work really well for the user and their loved ones. In particular, Tranquility makes an OverNight pull-on type product that holds over a quart of liquid, as well as a taper tap diaper (called All-Through The Night) which also holds about the same. These solutions have helped a lot of people.

I recently had a Foley catheter for six weeks. Just to let you know some of the side effects I experienced were irritation around the site, discomfort sitting and walking and increased bladder infections. But it might be worth a try.

To people with MS, believe me, I know.  I've survived MS for over half my life, and spent the last 20 years incontinent.  Believe me when I say that getting AWAY from catheters (indwelling that is, such as Foley, as opposed to those used by some patients for intermittent catheterization, in cases where the problem is an inability to urinate), has changed the mortality and morbidity statistics significantly.

 

Although as noted above people with neurogenic bladder and retention issues have to use intermittent catheterization to void the bladder at all, those who suffer urge incontinence or secondary incontinence or just a frequent need to urinate, even if they really don't have too are better served by adult diaper type products.

 

Note that this assumes the person has a reasonably diligent caregiver, or can care for themselves, as even the most modern products, despite Ph and other ingredients to stop ammonia production, should still NOT be worn for extensive periods when wet.  Further the skin should be well and completely dried between each change and the caregiver should be particularly on the look for pressure sores.  Still, other than an external catheter that can't be used by females, it IS the best alternative, and may even be better than the external condom type catheters for men as well (I for instance have a terrible reaction to them and my skin begins to dissolve).

 

In the end it's up to the individual, but looking at potential outcomes, it is almost always best to stay away from catheters or catheterization unless it's absolutely CRITICALLY medically necessary to so.  The use of catheters as common practice in nursing ended years ago, after they found out how many of their patients were dying prematurely because of it.