ETA: Where is FIL? In a hospital ICU? In a Hospice? At home?
Depending on where he is, the facility may NOT even, let a baby, be there.
So, have you/your Husband thought of that? Or asked the facility where your FIL is?
When my late Dad was very ill and in a hospital, they ONLY let immediate family enter his room. NO kids. Either.
And has FIL actually requested, that baby come to visit him?
Seems like you already booked the flight. And you all leave in 2 weeks. Better get your passports, and bring along your baby's vaccination records and insurance cards etc.
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Okay, not to be heartless either, as the previous responder said below: but I would not go, not take the baby.
This is an international flight, and trip.
How old is your baby?
Has it had all of his/her vaccinations?
I say this because, in my State, there was a 6 month old baby that died, due to Pertussis, that had not had his vaccinations. While on a trip, the baby got sick, from an Aunty who thought she just had a common cold. But it was Pertussis. Which displays differently in an adult, versus a baby. Anyway, the baby got real sick, by the time they got the baby to a Doc/Hospital, it was too late. The baby, died.
When would you be going on this trip?
Now? Winter? Spring? Summer?
The time/season of the year, for me at least, would matter.
We went to Europe one year for Christmas. Winter. It was very cold and snowing everyday. I got, seriously sick, when I was there. And had to go to emergency. My Asthma also got very affected. It was not fun. I spent our so called "vacation" very ill.
Next: it is a long flight. I have in-laws that live abroad in Europe. It is expensive. It takes us, 24 hours to fly there, one-way. We have NOT taken both of our kids there yet. Only my daughter has gone. When she was older. Not a baby. She was close to 8 when she went on that trip. And it was a long long flight. Even for an adult, it is a long flight that is hard to take.
If FIL wants to see her... you can do Skype. Like you have been doing.
Also, being he is ill, I highly doubt THEY will come to visit you.... even if you went there twice, already. Last year. And well, THEY opted to go on "their usual Spanish holiday instead." Not visiting, you, here. But you have gone, there.
I have in-laws like that. My Husband's family/Mom will not come here. Even if they can. They tell us we have to go there. Which, if we had millions of dollars in disposable cash, we could go there as often as they want. But we, cannot. It is not realistic, at all. For us.
Really, I would not go there, with the baby.
Your Husband can go, himself.
You should not have to be so conflicted and burdened about this.
And I am not meaning to be heartless about this.