One side of the triangle is the line through H1 perpendicular to AH1. Now find the midpoint G of EF. Then the length GH1 is the inradius. Construct circles centred at E and F with radius GH1. The intersection of the two circles is the incentre I. Construct the incircle centred at I with radius IE. The tangents to the incircle through A are the remaining two sides of the triangle.
Since there may be two intersections of the constructed circles, there may be up to two distinct solutions (one of which is a reflection of the other in the line AH1).
If the midpoint of the altitude coincides with the midpoint of chord EF of the inscribed circle, then the altitude is equal to two radii of the inscribed circle, which is impossible, as such a triangle does not exist.