Wow, complex question. Let's explain it more carefully, shall we?

OWFord LOVES Bill, that's a fact, and OWBill LOVES Ford. Love isn't the issue, it's how they deal with love.

Ford is Aroace in this universe, he loves Bill platonically, not romantically, although they do get into some more “romantic” situations for their own comfort, such as kissing and getting close to each other. He loves OWBill through manipulation and also outside manipulation: OWFord was made to love (not romantically) OWBill since it became a prophecy, that is, from birth Bill manipulated Ford to admire, feel safe and adore his image.

Here's a text I wrote some time ago explaining this.

“Everything was about him.

Ever since he was a child, Stanford Pines had been fascinated by triangles, it was almost an obsession. His parents didn't care, they thought he was strange enough with those six fingers.

But for Stanford, when his eyes saw it, he felt proud of those deformed hands, it seemed right for a few seconds.

And it had always been like that, ever since he was a baby, everything that reminded him of eyes and triangles made him feel comfortable. Cracks, wood fibers, clouds, asphalt, leaves, everything that could possibly form a triangle made him wiggle. He was obsessed with making triangle origami and drawing eye on them, he liked the feeling, he couldn't understand why…

Stanley always teased him about it, saying that he thought too much about geometry, or as he put it “boring shape stuff”, Stanford thought it was absurd but laughed anyway.

Money notes stirred him every time he saw that triangle, it seemed that something in that shape was calling him, it seemed that that eye was watching him. It was. A little scary.

But he got used to it, he got used to the feeling of being watched.

The color yellow attracted him, not as his favorite color, but the color that brought him calm, he didn't quite understand.

When he got older, he found out about the Illuminatis, and something inside him told him how ridiculous it was, how disrespectful they were! It was a symbol of peace and security, not of cruel mysteries. He was frustrated by this more than he understood.

One detail that his observant mind noticed was that the triangular shape always seemed to be in dangerous situations with him, and that was the reason he was safe. Like the time he was almost hit by a car while playing with Stanley and just then a post with a “stop” triangle fell into the street before the car lethally hit him. Or the time when he was threatened by bullies and a triangular-shaped rock fell from the school roof, hitting the school leader on the head and driving them away.

He thought it was funny, it seemed that his obsession with triangles also came from the triangle, he attracted triangles!

When he got the chance to go to his dream college, unfortunately his triangle luck didn't work out, he lost everything and Stanley was to blame.

When he got to the college he could go to, more triangles followed him, the symbol of his bedroom area, the prints on his shirts, he seemed to have returned to luck.

Another piece of luck for him was Fiddleford, his classmate with a green shirt with triangles! It was a sign that he was safe with that man! And he was right, he was his closest friend until he decided to move for his research to Gravity Falls!

There, not only were weirdos like him attracted, but so were triangles? It was confusing, but it was what he felt he would find the answers to.

And there it was, symbols, signs and stories, it was there, there where he would find the reason why his weirdness matched and attracted him so well to that shape he had seen so much of next to him.

Even that painting, that blessed painting.

It was him. He was what it was all about. He was the answer.

The all-seeing eye, and the words were right there.”

So basically, yes, Ford loves Bill's image because of clear manipulation, but he also started to love him after meeting him, loving traveling with him, taking care of the twins, and well, he saw Bill's way of giving back in a way of his own, being interdimensional and so on, maybe it's just the way he is….

Like a dream room, of course he would, he wants to see them having fun mainly, it wouldn't be a prison bubble after all.