Your Uncle is L12 venus posited in the 8th house of inheritance. The lot of truth falls at 3° Virgo on the MC. The lot ruler mercury seperates from a sextile with the lot and flows towards the lot, so does sun (arbiter of truth).
The sun is posited in the 3rd triplicity of the 9th house, the moon is the 3rd triplicity ruler, is exalted, angular and trine the in sect Jupiter, albeit in detriment and retro.
All this would suggest he is telling the truth.