Spit column that has underscore to multiple columns and also calculate age.

I have a table called clients and I'm trying to split the value  which contains underscore that is one column into multiple columns and I'm also trying to create a column that calculate the age of the person. Here is how the table looks like

USERIDVendors(dobyr)loginsource
10bta      yes       1976       yes    google_hope
25cwd      yes       1986       yes    google_hln_1045
45tyj      no        1990       no     bing_hln_4345
645io      no        1960       no     bing

The goal is to have that look like this:
USERID Vendors (dobyr) login Source1 Source2 Source3 Age
10bta      yes       1976       yes     google    hope       null      44
25cwd      yes       1986       yes     google    hln         1045     34
45tyj      no        1992       no      bing      hln         4345     28
645io      no        1960       no      bing      null       null      30   
So far, I've only been able to calculate the age but haven't been able to parse the source column
select *, datepart(year, CURRENT_TIMESTAMP) - dobyr as Age
FROM client