Kitten Quarantine

I was asked by a neighbour to watch their kitten for the week-end while they are away. To my surprise, he is very young (i'm guessing 4 weeks). I have him away from my 2 kittens since I have no idea if he is sick. I'm going to ask them if they will let me find him a home as he was born from either one of their barn cats or a feral and I highly doubt they will have him as an indoor pet. Also, while they are very nice people, this little kitten is not being taken care of appropriately. They said they were feeding him twice a day and given milk. I have formula left over from Cheddar and he was ravenous with hunger. Little guy literally bit off the nipple of the bottle!

So my question is, hypothetically speaking, if they say to go ahead and find him a home, how long should I quarantine from the other kittens? How would I know if he's sick and has something contagious?

A full 2 week quarrantine is called for. This allows time for any viruses he may have come in contact with to show themselves.

Poor little punkin. Glad he has you to look after him though.

Wondering why they don't get their barn cats fixed.............also where are the other babies............

Thank you. What kind of signs am I looking for?

Many farmers don't spay/neuter their barn cats, not sure why but it's common. The other babies unfortunately died. They said that when they realized they were there that they also noticed that the mom wasn't coming around.