Hello LR,
In these unusual circumstances – which finds you and your church as an independent Reformed (or at least Calvinistic as you hold to the LBC) congregation – Ruben's words above, "Has the church recognized and affirmed his calling", are the crux of the matter. If your local church has agreed, voted, called him to pastor you, before the Lord who is the Head of the church, you may consider him ordained or appointed to the office. Would you say he qualifies according to Paul's epistle to Titus 1:5-9:
"For this cause left I thee in Crete, that thou shouldest set in order the things that are wanting, and ordain elders in every city, as I had appointed thee: If any be blameless, the husband of one wife, having faithful children not accused of riot or unruly. For a bishop must be blameless, as the steward of God; not selfwilled, not soon angry, not given to wine, no striker, not given to filthy lucre; But a lover of hospitality, a lover of good men, sober, just, holy, temperate; Holding fast the faithful word as he hath been taught, that he may be able by sound doctrine both to exhort and to convince the gainsayers."
If you affirm his qualifications as per this Scripture – perhaps not perfectly, but essentially – then I would say your church's ordination, and not the Pentecostals, is valid for your church.