Your Immigration Expert
To bring a dependant to the UK on a Tier 2 visa there needs to be a commitment from the employer they will be willing to accommodate and financially support the family for the first month after arrival. A letter would usually be sufficient, assuming the employer holds a grade A licence to employ overseas nationals and the original application was filed correctly.
Alternatively, the employee can provide bank statements showing a minimum of £630 per dependent in the account for 90 days immediately prior to submission of the visa application.
I have provided a link to the site which may help you further and when you scroll down you will see the section on dependants of Tier 2 visa holders. UK Tier 2 visa sponsorship
I would urge you to speak to your UK employer who will have a direct point of contact within the immigration office, they will be able to assist in addressing this matter. The UK wants highly skilled workers and is both willing and able to assist your company with their sponsorship obligations for the employee and their family.