By Jon Jordan, NEWS 9

NORMAN, Oklahoma -- The search continues for a man missing in Norman. John Santos was last seen leaving his daughter's home Tuesday morning.

His family is desperate to find the 71-year-old, who suffers from Alzheimer's. There are seven levels of Alzheimer's with, with seven being the worst, and John Santos' family puts him at level five.

For 6 days or over 130 hours and counting.. no one has seen or heard John Santos. For most of the week family members have focused their search going up and down city streets here in Norman putting up flyers.

The search has broadened to the train tracks which Santos has been known to frequent.

"Until I find him, which I know we are, then my efforts are to keep going," said Sarah Santos, John's daughter. "I can't go home and sleep with air conditioning and a bed knowing he's out there in a field, or who knows where he is."

Family can't help but think the worst, however with Santos still out missing they're trying their best to stay positive.

"I don't let that take me down. We don't let it go there, it obviously has been in the back of all of our minds, but it's in the back and that's where it's gonna stay at this point," said Mistie Santos, John Santos' daughter-in-law.

Family members said the focus of their search is at night because they believe the 71-year-old is resting during the day and moving around at night. They organized a city wide search Sunday evening, asking people to go outside their homes because John Santos could be anywhere.

"It does come to be like 'Where can you be?' I mean I could find anyone it seems around here, for some reason just not him," said Mistie Santos."We are not letting it get us down, cause we know we are going to find him and we are going to bring him home to us."

If you would like to help the family with supplies, like spotlights and gas cards make a monetary donation, contact them at (405) 600-8007.