Is there a hair treatment you would recommend to help with dry and brittle hair?

I would recommend you look at investing in a haircare kit that would combat you problems , you need to treat your hair from the inside out as some products just mask the problem and deal with the surface only . I recommend Redken products for your problems the Allsoft range would be the best for you start with shampoo , conditioner and a leave in treatment. You will be suprised what a difference this alone will make, then you can add a treatment to your regeem as you progress. If you want a deeper treatment to boost your hair before starting your hair care regeem then visit your local Redken salon and ask for a chemistry treatment which they will carry out for you. Look at what you do at home of you use lots of heat appliances them make sure you protect your hair from this satin wear in Redken is fantastic for this. Try to use less heat less often will help .

Check out the karmin 4 step system ;)

Definitely Pro Naturals

Use a shampoo and conditioner.
Avoid exposing your hair to the sun.
It's very easy for you.
Try it.

Mahogany Naturals- Pre Shampoo Treatment
https://www.etsy.com/listing/95858282/mahogany-naturals-pre-shampoo-treatment

I recommend a brazilian keratin treatment for dry, brittle hair as it will restore hair to it's optimum condition straight away and also take all frizz out the hair so you dont need to style the hair with heat this will keep the hair at it's optimum condition.