Tier 2 general dependant - Absence limit for ILR

[seeweare]

Hi,
I am on Tier 2 general visa since Oct 2015. Earlier I was on Tier 2 ICT since Jun 2010 and switched to tier 2 general in UK.
My wife came to UK as my dependant in Jun 2012.
She is now in India since last 2 months and might have to stay for longer as its a medical emergency and health recovery of her father.
My question is how long can she stay in India without impacting ILR? Are there any limits on continuous absence and overall absence? We are planning to apply for ILR next year. Any guidance is greatly helpful.
Thank you.
Regards,
Ramana

[zimba]

There is no absence limit for PBS dependants whose visa was issued before 11 Jan 2018