Spouse visa - single parent

I would be grateful if someone can help me in regards to this question

I am a single father and have four children under the age of 16 and the youngest is 3 years old,
Their mother passed away
I am a British citizen so are my children
Recently I got married and wanted to apply for
A spouse visa but I am not working due to children

I get cared allowance for one child as he has medical problems
My other child get disability allowance lower rate
I am on income support and get child benefit and child tax

Can I still apply for spouse visa ?
If so how and what’s evidence do I need ?
Am I exempt from the U.K. government spouse visa requirements ?