".... But M, all in the same Group, and with a CEO who has stated he is against intervention for one of the OpCos in the Group but appears to be happy to take it for another.."
Since discrete figures have been published for BA, presumably - as you would expect - each company is run separately and maybe the Spanish divisions are not making much/any profit. IAG may also be being pressurised by the Spanish government to make minimal cuts and being rewarded for not doing so.
Anyway, as MM has pointed out ( and the optics are irrelevant ) no company can afford to use its cash reserves to employ 25% of its staff to sit at home for six or nine months, as it may need those reserves later if this terrible situation continues.