cat having trouble adjusting to new house

This is my first post.

About two and a half years ago i got my cats, Max and Tabby. Then about two to three months ago my family moved houses taking them with us. Tabby adjusted to the new house right a way. Max is still taking time to adjust. He's hides under a bed or in the sheets all day and only comes out to eat.

A recent behavior though, is he's been refusing to use the newly installed cat door leading to the garage, where the litter box is. (in the old house it was in the utility room. Now we just have a utility closet.) So he's been going to the bathroom on our couches. We did prop the cat door open for a while but then a mouse got in so we had to close the cat door. his food was in the garage but then we decided to move it into the kitchen where it wasn't so close to his litter box.

Any suggestions on how to get Max to use the cat door so he can get to his litterbox? (Tabby learned how to use the cat door the first day we had it. and she uses it frequently. it's just max who won't use it.)

Some cats just doesn't like those doors. Anyway you could put a litterbox inside for the other kitty?

If Max is still hiding and obviously not used to the house, the use of the cat door is the least of your problems.
I think you should wait until he is comfortable to the new surroundings. Then begin training him to get used to cat door. I assume he used one in the old house?

this may work ....id try putting the litter inside in area where max can clearly see and smell it...as for moving to a new house I know you said hes a bit shy and scared to look around , any move or change in surroundings can be stressfull for a kitty.... then as he starts to use the box keep moving it to you target area where you want him to keep using it ...I know it may look silly for a bit moving it around but this had worked for me when moving to new places ..Also If he is a male cat is he neutered ? a move may have prompted him to Mark his territiory...some uneuterd cats do this too...
good luck with litter box!! I know we all love our cats but Its kinna not fun to have them going where there not supposed to go ..

I would also suggest moving it inside until he adjusts. You could even get another litter box so that you have one inside and outside that way he can decide to start exploring outside on his own. Good luck!

Max has started coming out during the day and visiting. Yesterday, he even came out to say hi to our company who was here for christmas.

Although, he hasn't been using the cat door, by himself, I can see that he wants to. He watches tabby go in and out and then will go sniff the door and paw it.

we have started gently pushing him through the door so he will get the idea. but when he comes in after using the litter box, it takes him a while because he thinks he needs to use his paw to open it like a human uses a hand to open a door. he is getting better at opening the door with his paw.

Unfortunately, he still will occasionally pee or poop on our couch. does any body have any more Ideas.

there is no room in the house to add another litter box.

I would take him to the vet FIRST stress can cause illness in cats, inappropriate pooping is often a health issue and moving is stressful