Visiting Visa Usage

[piyush_choksi]

I am a having H1B Visa. My wife having H4 Visa. My mother has got Visting Visa for 10 years. I am planning to go to US along with my Wife and mother.
Since my mother has got visting Visa, she will he to return to India after six months.
Can my mother stay for a long time instead of Six months.
Can she go to canada for 1 or 2 days and again come back to US.

[immihelp]

If she tries to stay in US most of the times using visitor visa, she may be denied entry into US and deported back to India.