Alpine Helianthemun Rhodonthe Carneum can it be pruned to wood

You can trim it lightly now, if you want, though this often makes them look worse than they do already. Wait till it pauses in its flowering next year, after the first flush, and then cut it back hard, removing some of that dead stuff underneath as well. In other words, you will have to hard prune - but not before next Spring.
If it tolerates that and grows again, trim it lightly after flowering, and again in late August, to keep it growing tidily.

I cut all our Helianthemums back hard after flowering. They regrow happily. They are also dead easy to take cuttings from. Almost any piece will root, so take some of the ends of green growth that you hae and pot them up. Then if your pruning does not work, at least you will still have the plant.

I had one that was very slightly shaded by another plant and it got really leggy. I took some cuttings and planted them in full sun and those ones have formed much better denser plants.