H1B Status invalidated -? H1B status, and GC filing

My friend is working in USA on H1B Status just 2-3 years stay at present not used all 6 years.
His company filed a GC process, his PERM process cleared(approved).
His employer is going to apply Form I-140, he has some worries.

If His I-140 approved then his regular H1B status invalidated?

H1B status first 3 years (expires in Mar’2020) , his employer can file regular H1B
extension? to complete H1B 6 years norm.

Regular H1B current status and further extensions can be applied to use 6 years?
His GC process will go as is even I-140 approved, his regular H1b status as is?

I mean 2 parallel tracks can run

  1. H1B status - to complete 6 years, using current visa, filing extensions , approval etc
  2. GC process as is status progress

No, it will not.
Yes, they can
Yes, it can be two parallel tracks.
Yes, once 6 years are done, they can use I-140 approval for getting more extensions.