TICKS on pet rat

Question
My son in TX called to say he just discovered about 20 ticks on his pet rat.  Hundreds of ticks were also found in her rat food bag.  He made a quick trip to a pet store last night just as they were closing & got a tick shampoo for rats & used it.  He wasn't sure if it would kill or just repel the ticks.  Rat seems to be failing - sleeps, is in discomfort.  How can he remove the ticks without causing too much pain?  I don't think he has enought money for a vet.  Please help.  Thank you.  
P.S. My son may have gotten bit as well.

Answer
He is going to have to rub this rat with olive oil and suffocate the ticks, removing them with tweezers. Its going to be hard for the rat to sit still though.  A vet could sedate him.

How did they get on the rat?

I would try to find a way to see a vet in case there is a chance of infection.