My cat is being gone for 2 weeks for now.

Hi everyone.
I have a female cat and she is 1y and 6months old.
She gave birth twice. 
From the first birth we kept one male cat and the 3 others we gave away to another people. They (the mother and the son) were okay all the time. 
My cat got pregnant again and she had another 4 kittens. 
Her son (the male cat) is 6 months old and he was so caring about her kittens, he was cleaning them - actually helping his mother.

Before 2 weeks he disappeared from our street ( they live in our home but we let them go outside for a while and they come back).
We thought he was stolen but not anymore.

I just wanted to ask if anyone had an experience like this or? 
Is it possible that he left by himself because his mother had another kittens or he's looking for some adventures?

My mom is so stressed because she is so connected to the cats, she cries everyday and seems to be very upset about them.

What do you think guys?

Thank you a lot.

I'm very sorry that your cat is missing. it's very stressful not knowing where they are or if they are all right. 

Is the cat intact or has he been neutered? If he's intact he could very well be tomcatting around the neighborhood spreading "love" and litters of kittens with any unaltered females in the neighborhood. 6 months of age is about the right time for him to start doing this. This is probably the "adventures" he's looking for. 

What makes you think someone stole him? Is he a purebreed that someone would recognize if they saw him out wandering? Did someone threaten to take him? 

Please spay your 1 1/2 year old female ASAP. She will continue to have litter after litter if you don't. It's not good for her and you'll just have more kittens to take care of or find homes for. Shelters and rescues are already bursting at the seams with homeless cats and kittens. Many of these will end up being put to sleep because there just isn't room for more. When you re-home the kittens, please make it a condition that the new owner will spay or neuter the kitten after it's rehomed. All of these cats need to be fixed really. 

If you have an animal control or a type of humane society near you, you can check with them if they have picked the cat up or someone turned it in. Does he have a collar with tags or a microchip that they can scan? 

You can also talk to your neighbors. Show them a picture if you have one. If he's tomcatting around the neighborhood, chances are someone has seen him. Put up flyers offering a small reward for his return. You could also give a picture of him to your mail carrier and ask him/her to keep an eye out while he/she is out in the neighborhood making deliveries. 

Good luck. I hope you find him or he comes home on his own and that he is unharmed and healthy. 

From what I've heard from people a few things that might work.

You can maybe leave his blanket and bed and things his mother touches often (and smells like her) outside so he could follow the scent. You can also maybe leave food and water if you want. I'm not sure how effective this is but I know an old friend did this once. It wont hurt to try. I hope you find your cat