A friend of mine wrote
Whoever able to understand these few words [...] may draw my attention.
First, I told him to write "Anyone who is able to understand [...]", but he said he wants to keep the word "Whoever". Ok. With that assumption, for me, it would sound better if he said "Whoever being able to understand these few words [...] may draw my attention."
My question: Would you say that his sentence is correct without adding any word between "Whoever" and "able"?