HELP working out VLOOK formula i need to use across tabs

I think my mind is just frazzled but I need help working out the vlook formula for the attached spreadsheet.
I'm trying to use a vlook up across multiple tabs. (hopefully I've not had a shocker and been trying the wrong approach)

I want the summary tab to search the '3 group tabs' on name, and then to return the number of days for each month. So the summary tab will effectively show the total days for each person (based on the group tabs)

Any help would be much appreciated!