when i started tying my keskee, i also had a problem with hair breakage and loss. it's called "traction alopecia", and it's pretty common among turban wearing sikhs. if you catch it early, you can reverse it. unfortunately, if you ignore it too long, the hair loss will be permanent. i managed to reverse it in myself, here's what i changed:
when you wash your kes, don't use shampoo every day. this strips out the natural oils and weakens the hair. use a good conditioner or just plain cold water. you only need shampoo once a week or less. some people never use shampoo. that's ok too.
when you sleep, try to avoid tying the keskee into the kes. or if you do, don't leave it too loose. if it comes off during the night, all of the weight of the keskee pulls your kes out. you can keep the joodha loose, but tie the rest tight around the back of your head to keep it secure through the night. avoid putting tension on the kes whenever possible.
use a high quality oil that doesn't clog the hair follicles. as veerjee said above, almond oil is the best for this.
use a big, wide toothed kanga, and comb gently. don't pull the hair from the scalp when you comb it, hold it in your hand and comb below your hand.
even if you don't shower in cold water, at least wash your kes in cold water. this keeps the pores and follicles closed and tight and keeps dirt out of them.
i've been keeping kes for only four years now, and wearing a keskee tied into my kes for about 3.5 years of that time. my kes is now down to the back of my legs and still growing, so i totally swear by these methods. i hope it works for you too.