Biscuit you are so right to state that saying DD should sort it out with SIL is no help
SIL has a degree of OCD, so is very 'rule bound'
He has publicly said that he is delighted that we are now living nearer, and in September, just after we arrived, was only too happy for us to collect the children from school and have them here for a couple of hours so that DD could help him with some aspects of his work, which she does in addition to her own employment.
He isn't selfish per say, just has a different view of life, having been brought up in a rather old fashioned household where father was the breadwinner and mother did occasional voluntary work.
His job is extremely important, we understand that, and he has many pressures, and difficult people to deal with. In some ways he has been promoted before he was ready, but it is as it is.
There is minimal risk to there being a transference of the virus either way, as ostensibly we have all been self isolating since Christmas day.
This isn't about us being desperate to see the grandchildren, we have been 200 miles away from them until now, so could happily wait a little longer. It is just the fact that we could be helping out our DD
Meals and ironing?
SIL does the ironing, he always has done.
Meals, he helps out there a little as well.
It is just the childcare/supervision that he shuts off from while he is working in his study all day.
I know that many , many other families are in the same situation, it is just frustrating when I could be relieving them both a little by sticking to the rules but having the children occasionally.