My friend has a drawf gourami and he said that it has lost some of the blueish color on its head and that its head is looking kinda dirty grayish.The grayish color/blotching extends to just before its gills.
He asked me be I couldn't help him. He said that the dwarf gourami is housed with two mollies one black adn one dalmation, in a 10 or 15g tank not for sure which.

Color change can be due to a lot of different things, from diet to lighting. If he's had the fish for a while, but it's only now losing color, then it's probably due either to stress or to diet. A lot of fish can get less vibrant if they're unhappy in their environment (it's kind of the fish equivalent of getting grey hairs).

I'm pretty sure the blue color on gouramis comes from chromatophores - specifically cyanophores, which have the dye phycocyanin in them. This dye usually comes from food, so try feeding the gourami a variety of different foods (usually, no one food has everything your fishes need). I hope this helps!

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The gourami didn't make it in the end he had dark blotches in the area around where his stringy things come out and front fins. He ran into tankside and started to sezuire for 10 seconds then nothing.

The tank now has two mollies (one black & one dalmation) that was bout to be killed by nieghbor's child, I recycled the tank before I put them in the tank.

And I tought that kid how to maintain a aquarium with the parents permission