Anjalik,
This is a follow up post pursuant to your pm. The admission of your mother in the UK as a dependent would be dealt with outside the immigration rules because you are not
settled in the UK i.e. you do not have Indefinite Leave To Remain or British Citizenship.
IMHO the chances of a successful application for your mother to be included/come as a dependent to the UK with your wife and kids is low to non existent as things stand i.e.
1. You are on year 1 of HSMP - this may or may not be renewed.
2. You are working on a contract basis.
3. You have only recently entered the UK - consequently you are unlikely to have any significant savings to demonstrate the required level of support for two adults and 2 children.
Wait until you have the 3 year HSMP extension then apply for her to come to the UK - you need to put forward the compassionate grounds the application should consider. You primarily have to show that your mother has no other relative she can turn to - this must be out of circumstances rather than choice and thus the bruden of proof is solely with you.
An application to enter the UK as a visitor would be considered under the immigration rules with a focus on returnability after the visit. IMHO it would be easier for your mother to get a visitors visa while your wife and kids are still abroad.
Note that as always this is just my opinion. You may wish to seek further legal advice on the matter. Any person providing such advice must authorised by the
Office of The Immigration Services Commissioner unless otherwise exempt e.g. lawyers.
Hope that helps