What happened to my husbands uncle?

Yes it can, and it will answer the question you seek when you addressed specifically, ‘Did my husbands uncle commit suicide? Counting from the 7th house to represent your husband, count to the 4th house for your husbands Father, from there count 3 more houses to reach your husbands uncle, his Father’s brother, his uncle which will be the 12th of the chart. The 7th house would be his uncles 8th house that registers situations you have requested. Scorpio is on that house ruled of Pluto and Mars, and as you say Mars is in his Fall, in the 4th house (3rd) from the uncles first house (12th). The 4th house is ruled by the Moon, with Cancer on its cusp which is the sign on the natural 4th house of the zodiac that speaks of endings.

I don’t see the coordinates for the chart for Long. and Lat. of where you are, and I would like to have these for making up the chart from a different program with your permission, but I will understand if you deny me those coordinates for privacy sake.
Moon is at the 29th degree in Gemini, a degree signet that often is linked to endings, while she has also left the square(s) to the stellium of Saturn, (denial, death), Venus retrograde in Pisces (exalted in her sacrifice in Pisces) North Node (is there a legacy involved(?), Mercury retrograde in Pisces-a hidden awareness, of Pisces events, being in his uncles 12th from the 12th house of ‘self un-doings’, suicide and the like. All types of troubles that can be linked to; murder, death, kidnapping that put the life in peril committed by others and the self alike. Moon squaring Neptune jus leaving the stellium as he has entered just recently Aries is another testimony the uncle most likely is not on the earth anymore, having committed suicide or met with an untimely event that has its link in his death. The Moon tells us as she traveled through Gemini (ruler of relatives natural 3rd) squaring (obstacle) all those planets your ‘feelings’ of psychic senses are more than likely correct which prevents the uncles contact with your husband.
Before I delineate any further may I have the coordinates to the chart? Your chart is difficult for my old eyes to see, I’m 72 years of age.