[souffle]

If the blood is a dark reddish brown this indicates it is coming from higher up and is not just a little cut or something. It is usually from the womb and can be due to either a tumour in the womb or an infection. Is she drinking more than normal would she say? Drinking more is often the first sign of a pyometra and the hammy can appear quite well otherwise. A tumour that is bleeding though is always a worry as it must be affecting the organs inside and a constant blood loss weakens the hamster. At her age it is unlikely to be operable as she is an elderly little lady now but some treatment with some antibiotics could keep her comfortable for a while yet and may stop the bleed.
It is hard when your parents don't agree she needs seen. Ask your mum what she would do if she suddenly had abnormal bleeding. I bet she would go to the doctor so maybe she would see that your hammy needs to be seen too? Perhaps offer to do some chores to earn the money for a vet visit?
I've never had a female with blood spotting for no reason so I really don't believe that spotting is common. I hope you can sort it out and it works out well for you both. You are a very caring owner I can see. x