help on parents situation(posted before, but situation changed a

Hi,

any help/suggestion is appreciated. I posted this before, but now situation changed a little bit.

My dad came to US on B-2 in 1/2006,
he suffered bell's syndrom in 2/2006 and was rushed to emergency, stayed in hospital in 3 days.
then he was advised to apply medicaid,
medicaid was approved, not denied(just get told by hospital) in 4/2006.
5/2006, B-2 extension was submitted requesting extension of stay for further treatment
now got letter from vermont center asking for proof of payment.

Now what should I do? have the following question:
1. will this medicaid application affect their green card application which will be next year.(I will be naturalized end of this year).
2. For B-2 extension right now, how much chance of denial if we submit the medicaid approval notice.(requested by immigration office to be submitted by end of september and we request the extension to be 1/10/2007)
3. Can submit an appeal if denied in that case it's more or less around Dec/Jan by then???

appreciate any help.