GTA San Andreas Help Please!! Ps2!

Hello,
I have started playing san andreas ages ago but didnt complete it. I have just started playing it again and have completed a few missions but i have got to the mission 'reuniting the families' and I dont know where tgo start it at. I have a walkthrough that says the name of the mission and where to start it and it says sweets house and that i have to go to his house between the hours of 9:00am and 17:00 but When i got there there was no red marker to start the mission.
could someone please help me?