Several patches ago, some thralls began having a “preference” for a weapon. For instance, my Black Hand Captain would slice and dice with a pike, but I gave him a truncheon and he just stood there. Notice I speak of him in past tense.
When they come out of the wheel, look at their default weapon. If it’s a pike, you may need to keep them with a 2-hander. If they came out with a 1-handed weapon, often a two-hander will not work, and they’ll just stand there watching you get beaten up. Try Telith’s Lament on this thrall, and then try Sorrow on a thrall who came out with a Greatsword or pike.
This thrall can use any two handed sword, pike, axe what ever I give him except for Telith’s Sorrow. So, I don’t think what you are saying about “thrall’s preference” is correct.