
Persevere with the bottle feeding. Puppies can start on solid food from about 10 days whether they have their eyes open or not. Just put the mashed liquidy food in your hand and the puppy will take it after a few goes. Don't know what breed but have done this with labs who were very hungry at 7 days.
Any rearing of a litter is exhausting but hand rearing is particularly hard but very very rewarding, although that is hard to see at the moment. Is your friend on her own or does she have a partner / children to help?
If she is on her own or has no one to help the best thing you can do is go over at least once a day if you can and look after the puppy whilst she has 2 - 3 hrs of sleep. This helped me so much when I was hand rearing a litter. With no help the early hours are the hardest so it is nice to have a few hours sleep with help from a friend around the 7pm mark so that you can make it emotionally and mentally through the night. If you can't be there to help then be on the end of the phone.
The best advice I had from a friend who does not breed but has a lot of common sense 2 years ago when I was handrearing was.............go to bed and set your alarm for 4 hours time, the puppy will be fine. It was easy to sleep cos of exhaustion and that 4 hours made it possible to cope with the puppies and everything else the next day and for the week after. PLEASE DON'T DO THIS FOR AT LEAST ANOTHER WEEK THOUGH, MINE WERE 2 WEEKS OLD. No harm came to the pups they were a bit grumpy when i got up BUT I was able to cope. I'm sure others wouldn't recommend this but your friend needs care as well as the puppies and she is no good ill.
In a few weeks she will have started to get some sleep and will see the rewarding side of the puppy. Puppies who are hand raised are very people orientated and extremely cuddley. If your friend keeps the puppy as the pup goes she will be proud of rearing him / her herself.