The fundamental proposition of materialism is that matter is the only reality. Therefore consciousness is nothing but brain activity. However, among researchers in neuroscience and consciousness studies there is no consensus. 

This is only true in the same way that there's no consensus about climate change because I can find one or more people with PhDs who don't agree it exists.

  In biology and psychology the credit-rating of materialism is falling fast. 

I mean... Source...? His 2009 argument was that "there is still no proof that life and minds can be explained by physics and chemistry alone.", and again, that's true only for a tiny percentage of scientists. I don't think materialists ever promised to prove any of Kant's three paralogisms: "unified consciousness exists", "there was a first moment that set determinism in motion", and "god/cosmological purpose is, in some sense, real". You can complain about this, but it's not like Sheldrake has a different approach in mind; he's a scientist like the rest, just with different assumptions and goals. And I don't see how any of that changes the feasibility of knowing the definitionally unknowable.

  And by giving up the pretence that the ultimate answers are already known, the sciences will be freer—and more fun.

I think we can all agree with this, even if we don't agree that "materialism" is at fault. No good materialist should confidently say that we know the ultimate answers to any particular question -- after all, we're currently working with two separate "corresponding" systems of physics, biological taxonomy is in the process of dissolving completely in the face cladistics, molecular/genetic biology has about a million unanswered questions, and we're learning new things about the universe every time we make a bigger telescope. We are far from the finish line, if such a thing even exists at all. Even if it does, it won't include an answer on the purpose of the cosmos.