My friend ask me to doggie sit her two pit bulls for a couple of weeks. She was kicked out of her current residents because the land owner was scared of these big babies. My question is how do I help the babies to cope with the separation from the human mother? The boy is almost 3 years old and the girl is 6 months old.

If there are some sort of clothing (sock, t-shirt) with the owner's original scent on it... it should help.

My dog used to get separation anxiety and I would sleep in a shirt at night, leave it in her bed during the day and it seemed to help a little.

Sappy, the smelly tshirt is always a good thing to do but dogs are pretty resilient. Just give them lots of exercise to tire them out. A bored dog can be a problem dog. Work on basic training issues with them so that they recognize you are someone they need to listen to and follow. If this is only a couple of weeks, they should be fine.