How long approximately time to get the GC if my USC mother can put the file under F1 category ?

Yep, currently about 7-8 years. The Visa Bulletin publishes the wait-time.

I agree with my colleague - it's more of a question of when the child will get the certificate rather than when the child will be a citizen (as...

I left US because my father died, before AP and H4 approval. How should I re-enter the country? What should I do?

I agree with my colleagues - H-4 or wait for the AP document to be issued.

Can I stay in US longer or permanently if I have B1/B2 visa. What form should I fill out

I agree with my colleagues. This situation goes beyond the filing of forms. It's wise to consult with an immigration attorney.

Can i remove conditions from my 2-year greencard

This is actually not a question of IF you can remove the conditions from your green card. You are REQUIRED to apply to remove the conditions. ...

Yes, 4 years and 9 month after the date you became an LPR.

Any idea whether H4 EAD rule will be implemented or not ?

Certainly possible but nothing set in stone yet!

What is an Affidavit for Immigration? Don't know if I should sign the petition for my friend in order for him to become a US Res

I agree with my colleagues - the I-864 is an actual contract, so you'll have certain obligations in certain situations. It's worth it to consult...

If first entry was not inspected and 2nd entry is inspected do I still need waiver

Why were you paroled in the second time? It's best to run the entire situation by an immigration attorney.

Eligible to adjust in the USA?

Are you working with an immigration attorney? Best to run the full scenario by one.