Tier 2 extension or ILR?

[ukvisat2]

Following is timeline of my friend, who is on tier 2 visa.

• tier 2 visa issue date: 01-01-2013 (entered in UK on 15/02/2013)
  current visa expiry date: 14-10-2017 (Saturday)
  Two dependents joined in UK after 13 months (01 March 2014)

He has another COS for 2 years (3rd tier 2 extension).
He is short of 50 days (14-10-2017 to 03-12-2017) according to ILR guidance.

What do you suggest about varying the tier 2 extension application to ILR? would it be risky?

What would be better option for tier 2 and PBS dependent applicants?

[Djsuccess]

why do you think that his extension application will not be approved within 50 days?

[ukvisat2]

I think that usually tier 2 extension application processed within 8 weeks (56 days).
Is there anyway to delay the tier 2 extension application time to vary the application to ILR?