if he wants to be a christian fundamentalist then he can do that. God is his judge not I.
Rom 14:15-23 (YLT)
and if through victuals thy brother is grieved, no more dost thou walk according to love; do not with thy victuals destroy that one for whom Christ died. Let not, then, your good be evil spoken of, for the reign of God is not eating and drinking, but righteousness, and peace, and joy in the Holy Spirit; for he who in these things is serving the Christ, is acceptable to God and approved of men. So, then, the things of peace may we pursue, and the things of building up one another; for the sake of victuals cast not down the work of God; all things, indeed, are pure, but evil is to the man who is eating through stumbling. Right it is not to eat flesh, nor to drink wine, nor to do anything in which thy brother doth stumble, or is made to fall, or is weak. Thou hast faith! to thyself have it before God; happy is he who is not judging himself in what he doth approve, and he who is making a difference, if he may eat, hath been condemned, because it is not of faith; and all that is not of faith is sin.
G4102 πίστις pistis (pis'-tis) n.
1. persuasion, i.e. credence
2. (morally) conviction (of religious truth, or the truthfulness of God or a religious teacher)
3. (especially) reliance upon Christ for salvation
4. (abstractly) constancy in such profession
5. (by extension) the system of religious (Gospel) truth itself
[from G3982]
KJV: assurance, belief, believe, faith, fidelity
Root(s): G3982
G3982 πείθω peitho (pei'-tho) v.
1. to convince (by argument, true or false)
2. (by analogy) to pacify or conciliate (by other fair means)
3. (reflexively or passively) to assent (to evidence or authority), to rely (by inward certainty)
[a primary verb]
KJV: agree, assure, believe, have confidence, be (wax) conflent, make friend, obey, persuade, trust, yield